Lakes are carbon dioxide(CO_(2))and methane(CH_(4))emission hotspots,whose associated flux is spatially vari-able.Many studies have investigated the impact of microorganisms and environmental factors on CO_(2) and CH_...Lakes are carbon dioxide(CO_(2))and methane(CH_(4))emission hotspots,whose associated flux is spatially vari-able.Many studies have investigated the impact of microorganisms and environmental factors on CO_(2) and CH_(4) emissions between different lakes.However,the carbon emissions and their influencing factors of different areas within a single lake remain poorly understood.Accordingly,this study investigates CO_(2) and CH_(4) emission hetero-geneity in a large floodplain lake system and distribution characteristics of associated functional microorganisms.Findings show that mean CO_(2) and CH_(4) flux values in the sub lake area were 62.03±24.21 mg/(m2·day)and 5.97±3.2μg/(m2·day),which were greater by factors of 1.78 and 2.96 compared to the water channel and the main lake area,respectively.The alpha diversity of methanogens in the sub lake area was lower than that in the main lake and water channel areas.The abundance of methanogens in bottom water layer was higher compared with the middle and surface layers.Conversely,the abundance of methane(CH_(4))-oxidizing bacteria in the surface layer was higher than that in the bottom layer.Additionally,the composition of methanogen and CH_(4)-oxidizing bacterial community,chlorophyll a(Chl-a),pH,total phosphorus(TP)and dissolved organic carbon(DOC)con-tent constituted the dominate driving factors affecting lake C emissions.Results from this study can be used to improve our understanding of lake spatial heterogeneous of CO_(2) and CH_(4) emission and the driving mechanisms within floodplain lakes under the coupling effects of functional C microorganisms and environmental factors.展开更多
Ammonia(NH3)has been widely recognized as a key precursor of atmospheric secondary aerosol formation.Vehicle emission is a major source of urban atmospheric NH3.With the tightening of emission standards and the growin...Ammonia(NH3)has been widely recognized as a key precursor of atmospheric secondary aerosol formation.Vehicle emission is a major source of urban atmospheric NH3.With the tightening of emission standards and the growing trend of vehicle fleet electrification,it is imperative to update the emission factors for NH3 from real-world on-road fleets.In this study,a tunnel measurement was conducted in the urban area of Tianjin,China.The fleet-average NH3 emission factor(EF)was 11.2 mg/(km·veh),significantly lower than those in previous studies,showing the benefit of emission standard updating.Through a multiple linear regression analysis,the EFs of light-duty gasoline vehicles,light-duty diesel vehicles,and heavy-duty diesel vehicles(HDDVs)were estimated to be 5.7±0.6 mg/(km·veh),40.8±5.1 mg/(km·veh),and 160.2±16.6 mg/(km·veh),respectively.Based on the results from this study,we found that HDDVs,which comprise<3%of the total vehicles may contribute approximately 22%of total NH3 emissions in Tianjin.Our results highlight NH3 emissions from HDDVs,a previously potentially overlooked source of NH3 emissions in urban areas.The actual on-road NH3 emissions from HDDVs may exceed current expectations,posing a growing concern for the future.展开更多
Fiber-structured ion sensors have gained traction in health monitoring and medical diagnostics owing to their structural flexibility,enhanced sensitivity,and suitability for integration into wearable devices.This stud...Fiber-structured ion sensors have gained traction in health monitoring and medical diagnostics owing to their structural flexibility,enhanced sensitivity,and suitability for integration into wearable devices.This study employed a simple and efficient solutionbased process to fabricate nanofibers containing aggregation-induced emission(AIE)dyes.The resulting AIE nanofibers exhibited stable and intense fluorescence,nanosecond fluorescence lifetime,and low-loss light transport when functioning as active waveguides.Additionally,crossed nanofiber intersections exhibited diffraction-limited emission spots.The AIE nanofibers demonstrate efficient and ionspecific fluorescence quenching in response to Ag^(+).These results support the development of sensing units capable of operating in liquid environments or in direct contact with skin or tissues,facilitating real-time monitoring of ion concentrations for personalized healthcare management.展开更多
Atmospheric CO_(2) concentrations are predominantly regulated by multiple emission sources,with industrial emis-sions representing a critical anthropogenic driver that significantly influences temporal and spatial het...Atmospheric CO_(2) concentrations are predominantly regulated by multiple emission sources,with industrial emis-sions representing a critical anthropogenic driver that significantly influences temporal and spatial heterogeneity in regional CO_(2) patterns.This study investigated the spatiotemporal distribution of atmospheric CO_(2) in Pucheng and Nanping industrial parks,Nanping City,by conducting field experiments using two coherent differential absorption lidars from 1 August to 31 October 2024.Results showed that the spatial distributions of CO_(2) emis-sions within a 3 km radius were mapped,and the local diffusion processes were clarified.CO_(2) patterns varied differently in two industrial parks over the three-month period:Average CO_(2) concentrations in non-emission areas were 422.4 ppm in Pucheng and 408.7 ppm in Nanping,with the former experiencing higher and more variable carbon emissions;Correlation analysis indicated that synthetic leather factories in Pucheng contributed more to SO_(2) and NO_(x) levels compared to the chemical plant in Nanping;In Pucheng,CO_(2) concentrations were transported from the north at ground-level wind speeds exceeding 4 m/s,while in Nanping,the concentrations dispersed gradually with increasing wind speeds;Forward trajectory simulations revealed that the peak-emission from Pucheng primarily affected southern Fujian,northeastern Jiangxi,and southern Anhui,while the peak-emission from Nanping influenced central and western Fujian and northeastern Jiangxi.Besides,emissions in both industrial parks were higher on weekdays and lower on weekends,reflecting changes in industrial activi-ties.The study underscores the potential of lidar technology for providing detailed insights into CO_(2) distribution and the interactions between emissions,wind patterns,and carbon transport.展开更多
Luminescent metal-organic frameworks(MOFs)have garnered significant attention due to their structural tunability and potential applications in solid-state lighting,bioimaging,sensing,anticounterfeiting,and other field...Luminescent metal-organic frameworks(MOFs)have garnered significant attention due to their structural tunability and potential applications in solid-state lighting,bioimaging,sensing,anticounterfeiting,and other fields.Nevertheless,due to the tendency of1,4-benzenedicarboxylic acid(BDC)to rotate within the framework,MOFs composed of it exhibit significant non-radiative energy dissipation and thus impair the emissive properties.In this study,efficient luminescence of MIL-140A nanocrystals(NCs)with BDC rotors as ligands is achieved by pressure treatment strategy.Pressure treatment effectively modulates the pore structure of the framework,enhancing the interactions between the N,N-dimethylformamide vip molecules and the BDC ligands.The enhanced host-vip interaction contributes to the structural rigidity of the MOF,thereby suppressing the rotation-induced excited-state energy loss.As a result,the pressure-treated MIL-140A NCs displayed bright blue-light emission,with the photoluminescence quantum yield increasing from an initial 6.8%to 69.2%.This study developed an effective strategy to improve the luminescence performance of rotor ligand MOFs,offers a new avenue for the rational design and synthesis of MOFs with superior luminescent properties.展开更多
The development of quantum materials for single-photon emission is crucial for the advancement of quantum information technology.Although significant advancements have been witnessed in recent years for single-photon ...The development of quantum materials for single-photon emission is crucial for the advancement of quantum information technology.Although significant advancements have been witnessed in recent years for single-photon sources in the near-infrared band(λ∼700–1000 nm),several challenges have yet to be addressed for ideal single-photon emission at the telecommunication band.In this study,we present a droplet-epitaxy strategy for O-band to C-band single-photon source-based semiconductor quantum dots(QDs)using metal-organic vaporphase epitaxy(MOVPE).By investigating the growth conditions of the epitaxial process,we have successfully synthesized InAs/InP QDs with narrow emission lines spanning a broad spectral range of λ∼1200–1600 nm.The morphological and optical properties of the samples were characterized using atomic force microscopy and microphotoluminescence spectroscopy.The recorded single-photon purity of a plain QD structure reaches g^((2))(0)=0.16,with a radiative recombination lifetime as short as 1.5 ns.This work provides a crucial platform for future research on integrated microcavity enhancement techniques and coupled QDs with other quantum photonics in the telecom bands,offering significant prospects for quantum network applications.展开更多
Nowadays,presynaptic dopaminergic positron emission tomography,which assesses deficiencies in dopamine synthesis,storage,and transport,is widely utilized for early diagnosis and differential diagnosis of parkinsonism....Nowadays,presynaptic dopaminergic positron emission tomography,which assesses deficiencies in dopamine synthesis,storage,and transport,is widely utilized for early diagnosis and differential diagnosis of parkinsonism.This review provides a comprehensive summary of the latest developments in the application of presynaptic dopaminergic positron emission tomography imaging in disorders that manifest parkinsonism.We conducted a thorough literature search using reputable databases such as PubMed and Web of Science.Selection criteria involved identifying peer-reviewed articles published within the last 5 years,with emphasis on their relevance to clinical applications.The findings from these studies highlight that presynaptic dopaminergic positron emission tomography has demonstrated potential not only in diagnosing and differentiating various Parkinsonian conditions but also in assessing disease severity and predicting prognosis.Moreover,when employed in conjunction with other imaging modalities and advanced analytical methods,presynaptic dopaminergic positron emission tomography has been validated as a reliable in vivo biomarker.This validation extends to screening and exploring potential neuropathological mechanisms associated with dopaminergic depletion.In summary,the insights gained from interpreting these studies are crucial for enhancing the effectiveness of preclinical investigations and clinical trials,ultimately advancing toward the goals of neuroregeneration in parkinsonian disorders.展开更多
Emission characteristics of biogenic volatile organic compounds(BVOCs)from dominant tree species in the subtropical pristine forests of China are extremely limited.Here we conducted in situ field measurements of BVOCs...Emission characteristics of biogenic volatile organic compounds(BVOCs)from dominant tree species in the subtropical pristine forests of China are extremely limited.Here we conducted in situ field measurements of BVOCs emissions from representative mature evergreen trees by using dynamic branch enclosures at four altitude gradients(600-1690ma.s.l.)in the Nanling Mountains of southern China.Composition characteristics as well as seasonal and altitudinal variations were analyzed.Standardized emission rates and canopyscale emission factors were then calculated.Results showed that BVOCs emission intensities in the wet season were generally higher than those in the dry season.Monoterpenes were the dominant BVOCs emitted from most broad-leaved trees,accounting for over 70%of the total.Schima superba,Yushania basihirsuta and Altingia chinensis had relatively high emission intensities and secondary pollutant formation potentials.The localized emission factors of isoprene were comparable to the defaults in the Model of Emissions of Gases and Aerosols fromNature(MEGAN),while emission factors of monoterpenes and sesquiterpenes were 2 to 58 times of those in the model.Our results can be used to update the current BVOCs emission inventory in MEGAN,thereby reducing the uncertainties of BVOCs emission estimations in forested regions of southern China.展开更多
China is the most important steel producer in the world,and its steel industry is one of themost carbon-intensive industries in China.Consequently,research on carbon emissions from the steel industry is crucial for Ch...China is the most important steel producer in the world,and its steel industry is one of themost carbon-intensive industries in China.Consequently,research on carbon emissions from the steel industry is crucial for China to achieve carbon neutrality and meet its sustainable global development goals.We constructed a carbon dioxide(CO_(2))emission model for China’s iron and steel industry froma life cycle perspective,conducted an empirical analysis based on data from2019,and calculated the CO_(2)emissions of the industry throughout its life cycle.Key emission reduction factors were identified using sensitivity analysis.The results demonstrated that the CO_(2)emission intensity of the steel industry was 2.33 ton CO_(2)/ton,and the production and manufacturing stages were the main sources of CO_(2)emissions,accounting for 89.84%of the total steel life-cycle emissions.Notably,fossil fuel combustion had the highest sensitivity to steel CO_(2)emissions,with a sensitivity coefficient of 0.68,reducing the amount of fossil fuel combustion by 20%and carbon emissions by 13.60%.The sensitivities of power structure optimization and scrap consumption were similar,while that of the transportation structure adjustment was the lowest,with a sensitivity coefficient of less than 0.1.Given the current strategic goals of peak carbon and carbon neutrality,it is in the best interest of the Chinese government to actively promote energy-saving and low-carbon technologies,increase the ratio of scrap steel to steelmaking,and build a new power system.展开更多
Majority of carbon emissions originate from fossil energy consumption,thus necessitating calculation and monitoring of carbon emissions from energy consumption.In this study,we utilized energy consumption data from Si...Majority of carbon emissions originate from fossil energy consumption,thus necessitating calculation and monitoring of carbon emissions from energy consumption.In this study,we utilized energy consumption data from Sichuan Province and Chongqing Municipality for the years 2000 to 2019 to estimate their statistical carbon emissions.We then employed nighttime light data to downscale and infer the spatial distribution of carbon emissions at the county level within the Chengdu-Chongqing urban agglomeration.Furthermore,we analyzed the spatial pattern of carbon emissions at the county level using the coefficient of variation and spatial autocorrelation,and we used the Geographically and Temporally Weighted Regression(GTWR)model to analyze the influencing factors of carbon emissions at this scale.The results of this study are as follows:(1)from 2000 to 2019,the overall carbon emissions in the Chengdu-Chongqing urban agglomeration showed an increasing trend followed by a decrease,with an average annual growth rate of 4.24%.However,in recent years,it has stabilized,and 2012 was the peak year for carbon emissions in the Chengdu-Chongqing urban agglomeration;(2)carbon emissions exhibited significant spatial clustering,with high-high clustering observed in the core urban areas of Chengdu and Chongqing and low-low clustering in the southern counties of the Chengdu-Chongqing urban agglomeration;(3)factors such as GDP,population(Pop),urbanization rate(Ur),and industrialization structure(Ic)all showed a significant influence on carbon emissions;(4)the spatial heterogeneity of each influencing factor was evident.展开更多
Biliary tract cancer(BTC)is a group of heterogeneous sporadic diseases,including intrahepatic,hilar,and distal cholangiocarcinoma,as well as gallbladder cancer.BTC is characterized by high invasiveness and extremely p...Biliary tract cancer(BTC)is a group of heterogeneous sporadic diseases,including intrahepatic,hilar,and distal cholangiocarcinoma,as well as gallbladder cancer.BTC is characterized by high invasiveness and extremely poor prognosis,with a global increased incidence due to intrahepatic cholangiocarcinoma(ICC).The 18Ffludeoxyglucose positron emission tomography(PET)computed tomography(18F-FDG PET/CT)combines glucose metabolic information(reflecting the glycolytic activity of tumor cells)with anatomical structure to assess tumor metabolic heterogeneity,systemic metastasis,and molecular characteristics noninvasively,overcoming the limitations of traditional imaging in the detection of micrometastases and recurrent lesions.18F-FDG PET/CT offers critical insights in clinical staging,therapeutic evaluation,and prognostic prediction of BTC.This article reviews research progress in this field over the past decade,with a particular focus on the advances made in the last 3 years,which have not been adequately summarized and recognized.The research paradigm in this field is shifting from qualitative to quantitative studies,and there have been significant breakthroughs in using 18F-FDG PET/CT metabolic information to predict gene expression in ICC.Radiomics and deep learning techniques have been applied to ICC for prognostic prediction and differential diagnosis.Additionally,PET/magnetic resonance imaging is increasingly demonstrating its value in this field.展开更多
Carbon emissions resulting from energy consumption have become a pressing issue for governments worldwide.Accurate estimation of carbon emissions using satellite remote sensing data has become a crucial research probl...Carbon emissions resulting from energy consumption have become a pressing issue for governments worldwide.Accurate estimation of carbon emissions using satellite remote sensing data has become a crucial research problem.Previous studies relied on statistical regression models that failed to capture the complex nonlinear relationships between carbon emissions and characteristic variables.In this study,we propose a machine learning algorithm for carbon emissions,a Bayesian optimized XGboost regression model,using multi-year energy carbon emission data and nighttime lights(NTL)remote sensing data from Shaanxi Province,China.Our results demonstrate that the XGboost algorithm outperforms linear regression and four other machine learning models,with an R^(2)of 0.906 and RMSE of 5.687.We observe an annual increase in carbon emissions,with high-emission counties primarily concentrated in northern and central Shaanxi Province,displaying a shift from discrete,sporadic points to contiguous,extended spatial distribution.Spatial autocorrelation clustering reveals predominantly high-high and low-low clustering patterns,with economically developed counties showing high-emission clustering and economically relatively backward counties displaying low-emission clustering.Our findings show that the use of NTL data and the XGboost algorithm can estimate and predict carbon emissionsmore accurately and provide a complementary reference for satellite remote sensing image data to serve carbon emission monitoring and assessment.This research provides an important theoretical basis for formulating practical carbon emission reduction policies and contributes to the development of techniques for accurate carbon emission estimation using remote sensing data.展开更多
Civil aviation is one of the industries facing the greatest challenge in reaching carbon neutrality by the middle of this century,and this sector also contributes to adverse impacts on the regional air quality and hum...Civil aviation is one of the industries facing the greatest challenge in reaching carbon neutrality by the middle of this century,and this sector also contributes to adverse impacts on the regional air quality and human health.China exhibits the second highest air passenger turnover worldwide.Our understanding of civil aviation emissionsmust be urgently enhanced,and themitigation potential should be explored.In this study,on the basis of real domestic flight information for 2019,we built a greenhouse gas and air pollution emission inventory for the civil aviation sector in China with the fuel flowmethod based on the cruise and other phases.We thoroughly analyzed emissions by region,aircraft and engine types,and aircraft age,based on which we designed four measures to evaluate the abatement potential.We found that the hydrocarbon(HC),CO,NO_(x),SO_(2),particulate matter(PM)and CO_(2)emissions in 2019 reached 79.9 kt(95%CI[51.6–114.5]),176.3 kt(95%CI[114.5–248.2]),304.2 kt(95%CI[203.4–420.7]),23.2 kt(95%CI[14.2–33.7]),1.0 kt(95%CI[0.61–1.44])and 87.0 Mt(95%CI[57.4–119.6]),respectively.The cruise phase was the major emission phase,accounting for 67%-87%of the total pollutant emissions.If four measures were jointly implemented,the HC,CO,NO_(x),SO_(2),PM and CO_(2)emissions could be reduced by 61%,54%,55%,45%,32%and 38%,respectively.Utilizing lower-emission aircraft and switching travel modes could substantially reduce civil aviation emissions in China.展开更多
Methane contributes to global warming,and livestock is one of the sources of methane production.However,methane emission studies using bibliometric tools in livestock are lacking.Given the negative impact of climate c...Methane contributes to global warming,and livestock is one of the sources of methane production.However,methane emission studies using bibliometric tools in livestock are lacking.Given the negative impact of climate change on the ecosystem and the rise in methane emissions,it is essential to conduct a bibliometrics study to provide an overview and research trends.We used the Bibliometrix package and VOSviewer to decipher bibliometric indices for methane emissions in cattle farms(MECF).Current dataset were collected from the Web of Science(Core Collection)database,and 8,998 publications were analyzed.The most co-occurring keywords scientists preferred were methane(1,528),greenhouse gas(443),methane emissions(440),and cattle(369).Methane was the most frequently used keyword in the published scientific literature.Thematic evolution of research themes and trend results highlighted carbon dioxide,methane,dairy cattle,cattle,and risk factors during 1999–2017.Chinese Academy of Sciences ranked on top with 485 publications,followed by Agriculture&Agri-Food Canada,University of Colorado,National Oceanic and Atmospheric Administration,and Aarhus University.Chinese Academy of Sciences was also the most cited organization,followed by the University of Colorado,Agriculture&Agri-Food Canada,National Oceanic and Atmospheric Administration,and United States Geological Survey.Source analysis showed that the Science of the Total Environment was cited with the highest total link strength.Science of the Total Environment ranked first in source core 1 with 290 citation frequencies,followed by Journal of Dairy Science with 223 citation frequencies.Currently,no bibliometric study has been conducted on MECF,and to fill this knowledge gap,we carried out this study to highlight methane emissions in cattle farms,aiming at a climate change perspective.In this regard,we focused on the research productivity of countries authors,journals and institutions,co-occurrence of keywords,evolution of research trends,and collaborative networking.Based on relevance degree of centrality,methane emissions and greenhouse gases appeared as basic themes,cattle,and dairy cattle appeared as emerging/declining themes,whereas,methane,greenhouse gas and nitrous oxide appeared to fall amongst basic and motor themes.On the other hand,beef cattle,rumen and dairy cow seem to be between motor and niche themes,and risk factors lie in niche themes.The present bibliometric analysis provides research progress on methane emissions in cattle farms.Current findings may provide a framework for understanding research trends and themes in MECF research.展开更多
Cutting farming-related methane emissions from ruminants is critical in the battle against climate change.Since scientists initially investigated the potential of marine macroalgae to reduce methane emissions,using se...Cutting farming-related methane emissions from ruminants is critical in the battle against climate change.Since scientists initially investigated the potential of marine macroalgae to reduce methane emissions,using seaweeds as an anti-methanogenic feed additive has become prevailing in recent years.Asparagopsis taxiformis is the preferred species because it contains a relatively higher concentration of bromoform.As a type of halogenated methane analogue,bromoform contained in A.taxiformis can specifically inhibit the activity of coenzyme M methyltransferase,thereby blocking the ruminal methanogenesis.However,bromoform is a potential toxin and ozone-depleting substance.In response,current research focuses on the effects of bromoform-enriched seaweed supplementation on ruminant productivity and safety,as well as the impact of large-scale cultivation of seaweeds on the atmospheric environment.The current research on seaweed still needs to be improved,especially in developing more species with low bromoform content,such as Bonnemaisonia hamifera,Dictyota bartayresii,and Cystoseira trinodis.Otherwise,seaweed is rich in bioactive substances and exhibits antibacterial,anti-inflammatory,and other physiological properties,but research on the role of these bioactive compounds in methane emissions is lacking.It is worthy of deeper investigation to identify more potential bioactive compounds.As a new focus of attention,seaweed has attracted the interest of many scientists.Nevertheless,seaweed still faces some challenges as a feed additive to ruminants,such as the residues of heavy metals(iodine and bromine)and bromoform in milk or meat,as well as the establishment of a supply chain for seaweed cultivation,preservation,and processing.We have concluded that the methane-reducing efficacy of seaweed is indisputable.However,its application as a commercial feed additive is still influenced by factors such as safety,costs,policy incentives,and regulations.展开更多
Nitrous oxide(N_(2)O),as an important gas affecting climate warming,is attracting attention from allwalks of life.This reviewaddresses N_(2)O emissions status in the adipic acid industry,a significant industrial green...Nitrous oxide(N_(2)O),as an important gas affecting climate warming,is attracting attention from allwalks of life.This reviewaddresses N_(2)O emissions status in the adipic acid industry,a significant industrial greenhouse gas source.It elucidates the N_(2)O emission mechanism and influencing factors in adipic acid production.It extensively evaluates N_(2)O emission accounting methods,including Intergovernmental Panel on Climate Change(IPCC)Guidelines,World Resources Institute(WRI)Protocol,and others.While the IPCC emission factor method offers simplicity and comparability,it may lack precision for facilities with advanced emission reduction measures.To address this,a combined modeling and monitoring approach is advocated.It scrutinizes modeling methods(statistical techniques,Greenhouse Gas and Air Pollution Interactions and Synergies,and Life-cycle Assessment)and highlights their reliance on specific data and perspectives.It emphasizes the growing importance of on-site monitoring with mid-IR technology.Additionally,it underscores the potential of aircraft-based and satellite remote sensing for comprehensive N_(2)O emissions data.The reviewalso highlights recent advancements in emission mitigation,particularly in adipic acid synthesis techniques,showing substantial potential for N_(2)O reduction.Innovative paradigms and strategies for N_(2)O mitigation in the adipic acid industry are presented,with a focus on achieving nitrogen oxides(NO_(x))-free production.These approaches hold promise for emission reduction,given the high removal efficiency in plant end-of-treatment processes.Various accounting methods,monitoring techniques,and mitigation strategies were integrated and analyzed to provides a comprehensive overview of N_(2)O emissions in the adipic acid industry,with the aim of guiding future research and policy initiatives.展开更多
As a significant city in the Yangtze River Delta regions,Hefei has experienced rapid changes in the sources of air pollution due to its high-speed economic development and urban expansion.However,there has been limite...As a significant city in the Yangtze River Delta regions,Hefei has experienced rapid changes in the sources of air pollution due to its high-speed economic development and urban expansion.However,there has been limited research in recent years on the spatial-temporal distribution and emission of its atmospheric pollutants.To address this,this study conducted mobile observations of urban roads using the Mobile-DOAS instrument from June 2021 to May 2022.The monitoring results exhibit a favourable consistent with TROPOMI satellite data and ground monitoring station data.Temporally,there were pronounced seasonal variations in air pollutants.Spatially,high concentration of HCHO and NO_(2)were closely associated with traffic congestion on roadways,while heightened SO_(2)levels were attributed to winter heating and industrial emissions.The study also revealed that with the implementation of road policies,the average vehicle speed increased by 95.4%,while the NO concentration decreased by 54.4%.In the estimation of urban NO_(x)emission flux,it was observed that in temporal terms,compared with inventory data,the emissions calculated viamobile measurements exhibitedmore distinct seasonal patterns,with the highest emission rate of 349 g/sec in winter and the lowest of 142 g/sec in summer.In spatial terms,the significant difference in emissions between the inner and outer ring roads also suggests the presence of the city’s primary NO_(x)emission sources in the area between these two rings.This study offers data support for formulating the next phase of air pollution control measures in urban areas.展开更多
The loaded rock experiences multiple stages of deformation.It starts with the formation of microcracks at low stresses(crack initiation,CI)and then transitions into unstable crack propagation(crack damage,CD)near the ...The loaded rock experiences multiple stages of deformation.It starts with the formation of microcracks at low stresses(crack initiation,CI)and then transitions into unstable crack propagation(crack damage,CD)near the ultimate strength.In this study,both the acoustic emission method(AEM)and the ultrasonic testing method(UTM)were used to examine the characteristics of AE parameters(b-value,peak frequency,frequency-band energy ratio,and fractal dimension)and ultrasonic(ULT)properties(velocity,amplitude,energy attenuation,and scattering attenuation)of bedded shale at CI,CD,and ultimate strength.The comparison involved analyzing the strain-based method(SBM),AEM,and UTM to determine the thresholds for damage stress.A fuzzy comprehensive evaluation model(FCEM)was created to describe the damage thresholds and hazard assessment.The results indicate that the optimal AE and ULT parameters for identifying CI and CD stress are ringing count,ultrasonic amplitude,energy attenuation,and scattering attenuation of the S-wave.Besides,damage thresholds were detected earlier by AE monitoring,ranging from 3 MPa to 10 MPa.CI and CD identified by UTM occurred later than SBM and AEM,and were in the range of 12 MPa.The b-value,peak frequency,energy ratio in the low-frequency band(0e62.5 kHz),correlation dimension,and sandbox dimension showed low values at the peak stress,while the energy ratio in a moderate-frequency band(187.5e281.25 kHz)and amplitude showed high values.The successful application of FCEM to laboratory testing of shales has demonstrated its ability to quantitatively identify AE/ULT precursors of seismic hazards associated with rock failure.展开更多
This paper proposes that China,under the challenge of balancing its development and security,can aim for the Paris Agreement's goal to limit global warming to no more than 2℃by actively seeking carbonpeak and car...This paper proposes that China,under the challenge of balancing its development and security,can aim for the Paris Agreement's goal to limit global warming to no more than 2℃by actively seeking carbonpeak and carbon-neutrality pathways that align with China's national conditions,rather than following the idealized path toward the 1.5℃target by initially relying on extensive negative-emission technologies such as direct air carbon capture and storage(DACCS).This work suggests that pursuing a 1.5℃target is increasingly less feasible for China,as it would potentially incur 3–4 times the cost of pursuing the 2℃target.With China being likely to achieve a peak in its emissions around 2028,at about 12.8 billion tonnes of anthropogenic carbon dioxide(CO_(2)),and become carbon neutral,projected global warming levels may be less severe after the 2050s than previously estimated.This could reduce the risk potential of climate tipping points and extreme events,especially considering that the other two major carbon emitters in the world(Europe and North America)have already passed their carbon peaks.While natural carbon sinks will contribute to China's carbon neutrality efforts,they are not expected to be decisive in the transition stages.This research also addresses the growing focus on climate overshoot,tipping points,extreme events,loss and damage,and methane reductions in international climate cooperation,emphasizing the need to balance these issues with China's development,security,and fairness considerations.China's pursuit of carbon neutrality will have significant implications for global emissions scenarios,warming levels,and extreme event projections,as well as for climate change hotspots of international concern,such as climate tipping points,the climate crisis,and the notion that the world has moved from a warming to a boiling era.Possible research recommendations for global emissions scenarios based on China's 2℃target pathway are also summarized.展开更多
To understand the smoke level and NO_(x)emission characteristics of in-use construction machinery in Beijing,we selected 905 construction machines in Beijing from August 2022 to April 2023 to monitor the emission leve...To understand the smoke level and NO_(x)emission characteristics of in-use construction machinery in Beijing,we selected 905 construction machines in Beijing from August 2022 to April 2023 to monitor the emission level of smoke and NO_(x).The exhaust smoke level and excessive emission situation of different machinery types were identified,and their NO_(x)emission levels were monitored according to the free acceleration method.We investigated the correlation of NO_(x)and smoke emission,and proposed suggestions for controlling pollution discharge from construction machinery in the future.The results show that the exhaust smoke level was 0–2.62 m^(−1),followed a log-normal distribution(μ=-1.73,δ=1.09,R^(2)=0.99),with a 5.64%exceedance rate.Differenceswere observed amongmachinery types,with low-power engine forklifts showing higher smoke levels.The NO_(x)emission range was 71–1516 ppm,followed a normal distribution(μ=565.54,δ=309.51,R^(2)=0.83).Differences among machinery types were relatively small.Engine rated net power had the most significant impact on NO_(x)emissions.Thus,NO_(x)emissions from construction machinery need further attention.Furthermore,we found a weak negative correlation(p<0.05)between the emission level of smoke and NO_(x),that is the synergic emission reduction effect is poor,emphasizing the need for NO_(x)emission limits.In the future,the oversight in Beijing should prioritize phasing out ChinaⅠand ChinaⅡmachinery,and monitor emissions from highpower engine ChinaⅢmachinery.展开更多
基金supported by the National Natural Science Foundation of China(No.42225103).
文摘Lakes are carbon dioxide(CO_(2))and methane(CH_(4))emission hotspots,whose associated flux is spatially vari-able.Many studies have investigated the impact of microorganisms and environmental factors on CO_(2) and CH_(4) emissions between different lakes.However,the carbon emissions and their influencing factors of different areas within a single lake remain poorly understood.Accordingly,this study investigates CO_(2) and CH_(4) emission hetero-geneity in a large floodplain lake system and distribution characteristics of associated functional microorganisms.Findings show that mean CO_(2) and CH_(4) flux values in the sub lake area were 62.03±24.21 mg/(m2·day)and 5.97±3.2μg/(m2·day),which were greater by factors of 1.78 and 2.96 compared to the water channel and the main lake area,respectively.The alpha diversity of methanogens in the sub lake area was lower than that in the main lake and water channel areas.The abundance of methanogens in bottom water layer was higher compared with the middle and surface layers.Conversely,the abundance of methane(CH_(4))-oxidizing bacteria in the surface layer was higher than that in the bottom layer.Additionally,the composition of methanogen and CH_(4)-oxidizing bacterial community,chlorophyll a(Chl-a),pH,total phosphorus(TP)and dissolved organic carbon(DOC)con-tent constituted the dominate driving factors affecting lake C emissions.Results from this study can be used to improve our understanding of lake spatial heterogeneous of CO_(2) and CH_(4) emission and the driving mechanisms within floodplain lakes under the coupling effects of functional C microorganisms and environmental factors.
基金supported by the National key research and development program of China(No.2022YFE0135000)the National Natural Science Foundation of China(No.42175123)the Natural Science Foundation of Tianjin(No.23JCJQJC00170).
文摘Ammonia(NH3)has been widely recognized as a key precursor of atmospheric secondary aerosol formation.Vehicle emission is a major source of urban atmospheric NH3.With the tightening of emission standards and the growing trend of vehicle fleet electrification,it is imperative to update the emission factors for NH3 from real-world on-road fleets.In this study,a tunnel measurement was conducted in the urban area of Tianjin,China.The fleet-average NH3 emission factor(EF)was 11.2 mg/(km·veh),significantly lower than those in previous studies,showing the benefit of emission standard updating.Through a multiple linear regression analysis,the EFs of light-duty gasoline vehicles,light-duty diesel vehicles,and heavy-duty diesel vehicles(HDDVs)were estimated to be 5.7±0.6 mg/(km·veh),40.8±5.1 mg/(km·veh),and 160.2±16.6 mg/(km·veh),respectively.Based on the results from this study,we found that HDDVs,which comprise<3%of the total vehicles may contribute approximately 22%of total NH3 emissions in Tianjin.Our results highlight NH3 emissions from HDDVs,a previously potentially overlooked source of NH3 emissions in urban areas.The actual on-road NH3 emissions from HDDVs may exceed current expectations,posing a growing concern for the future.
基金partially supported by the National Natural Science Foundation of China(Nos.11804120,61827822,and 22275072)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515030209)+1 种基金Research Projects from Guangzhou(Nos.2023A03J0018 and 2024A04J3712)Fundamental Research Funds for the Central Universities(No.21623412).
文摘Fiber-structured ion sensors have gained traction in health monitoring and medical diagnostics owing to their structural flexibility,enhanced sensitivity,and suitability for integration into wearable devices.This study employed a simple and efficient solutionbased process to fabricate nanofibers containing aggregation-induced emission(AIE)dyes.The resulting AIE nanofibers exhibited stable and intense fluorescence,nanosecond fluorescence lifetime,and low-loss light transport when functioning as active waveguides.Additionally,crossed nanofiber intersections exhibited diffraction-limited emission spots.The AIE nanofibers demonstrate efficient and ionspecific fluorescence quenching in response to Ag^(+).These results support the development of sensing units capable of operating in liquid environments or in direct contact with skin or tissues,facilitating real-time monitoring of ion concentrations for personalized healthcare management.
基金supported by the National Natural Science Foundation of China(Nos.42305147 and 42405138)the Natural Science Foundation of Jiangsu Province(No.BK20230428).
文摘Atmospheric CO_(2) concentrations are predominantly regulated by multiple emission sources,with industrial emis-sions representing a critical anthropogenic driver that significantly influences temporal and spatial heterogeneity in regional CO_(2) patterns.This study investigated the spatiotemporal distribution of atmospheric CO_(2) in Pucheng and Nanping industrial parks,Nanping City,by conducting field experiments using two coherent differential absorption lidars from 1 August to 31 October 2024.Results showed that the spatial distributions of CO_(2) emis-sions within a 3 km radius were mapped,and the local diffusion processes were clarified.CO_(2) patterns varied differently in two industrial parks over the three-month period:Average CO_(2) concentrations in non-emission areas were 422.4 ppm in Pucheng and 408.7 ppm in Nanping,with the former experiencing higher and more variable carbon emissions;Correlation analysis indicated that synthetic leather factories in Pucheng contributed more to SO_(2) and NO_(x) levels compared to the chemical plant in Nanping;In Pucheng,CO_(2) concentrations were transported from the north at ground-level wind speeds exceeding 4 m/s,while in Nanping,the concentrations dispersed gradually with increasing wind speeds;Forward trajectory simulations revealed that the peak-emission from Pucheng primarily affected southern Fujian,northeastern Jiangxi,and southern Anhui,while the peak-emission from Nanping influenced central and western Fujian and northeastern Jiangxi.Besides,emissions in both industrial parks were higher on weekdays and lower on weekends,reflecting changes in industrial activi-ties.The study underscores the potential of lidar technology for providing detailed insights into CO_(2) distribution and the interactions between emissions,wind patterns,and carbon transport.
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406200)the National Natural Science Foundation of China(No.12274177 and 12304261)the China Postdoctoral Science Foundation(No.2024M751076)。
文摘Luminescent metal-organic frameworks(MOFs)have garnered significant attention due to their structural tunability and potential applications in solid-state lighting,bioimaging,sensing,anticounterfeiting,and other fields.Nevertheless,due to the tendency of1,4-benzenedicarboxylic acid(BDC)to rotate within the framework,MOFs composed of it exhibit significant non-radiative energy dissipation and thus impair the emissive properties.In this study,efficient luminescence of MIL-140A nanocrystals(NCs)with BDC rotors as ligands is achieved by pressure treatment strategy.Pressure treatment effectively modulates the pore structure of the framework,enhancing the interactions between the N,N-dimethylformamide vip molecules and the BDC ligands.The enhanced host-vip interaction contributes to the structural rigidity of the MOF,thereby suppressing the rotation-induced excited-state energy loss.As a result,the pressure-treated MIL-140A NCs displayed bright blue-light emission,with the photoluminescence quantum yield increasing from an initial 6.8%to 69.2%.This study developed an effective strategy to improve the luminescence performance of rotor ligand MOFs,offers a new avenue for the rational design and synthesis of MOFs with superior luminescent properties.
基金supported by the National Natural Science Foundation of China (Grant Nos.12494604,12393834,12393831,62274014,6223501662335015)the National Key R&D Program of China (Grant No.2024YFA1208900)。
文摘The development of quantum materials for single-photon emission is crucial for the advancement of quantum information technology.Although significant advancements have been witnessed in recent years for single-photon sources in the near-infrared band(λ∼700–1000 nm),several challenges have yet to be addressed for ideal single-photon emission at the telecommunication band.In this study,we present a droplet-epitaxy strategy for O-band to C-band single-photon source-based semiconductor quantum dots(QDs)using metal-organic vaporphase epitaxy(MOVPE).By investigating the growth conditions of the epitaxial process,we have successfully synthesized InAs/InP QDs with narrow emission lines spanning a broad spectral range of λ∼1200–1600 nm.The morphological and optical properties of the samples were characterized using atomic force microscopy and microphotoluminescence spectroscopy.The recorded single-photon purity of a plain QD structure reaches g^((2))(0)=0.16,with a radiative recombination lifetime as short as 1.5 ns.This work provides a crucial platform for future research on integrated microcavity enhancement techniques and coupled QDs with other quantum photonics in the telecom bands,offering significant prospects for quantum network applications.
基金supported by the Research Project of the Shanghai Health Commission,No.2020YJZX0111(to CZ)the National Natural Science Foundation of China,Nos.82021002(to CZ),82272039(to CZ),82171252(to FL)+1 种基金a grant from the National Health Commission of People’s Republic of China(PRC),No.Pro20211231084249000238(to JW)Medical Innovation Research Project of Shanghai Science and Technology Commission,No.21Y11903300(to JG).
文摘Nowadays,presynaptic dopaminergic positron emission tomography,which assesses deficiencies in dopamine synthesis,storage,and transport,is widely utilized for early diagnosis and differential diagnosis of parkinsonism.This review provides a comprehensive summary of the latest developments in the application of presynaptic dopaminergic positron emission tomography imaging in disorders that manifest parkinsonism.We conducted a thorough literature search using reputable databases such as PubMed and Web of Science.Selection criteria involved identifying peer-reviewed articles published within the last 5 years,with emphasis on their relevance to clinical applications.The findings from these studies highlight that presynaptic dopaminergic positron emission tomography has demonstrated potential not only in diagnosing and differentiating various Parkinsonian conditions but also in assessing disease severity and predicting prognosis.Moreover,when employed in conjunction with other imaging modalities and advanced analytical methods,presynaptic dopaminergic positron emission tomography has been validated as a reliable in vivo biomarker.This validation extends to screening and exploring potential neuropathological mechanisms associated with dopaminergic depletion.In summary,the insights gained from interpreting these studies are crucial for enhancing the effectiveness of preclinical investigations and clinical trials,ultimately advancing toward the goals of neuroregeneration in parkinsonian disorders.
基金supported by the National Natural Science Foundation of China (NSFC)Projects (Nos.42205105,42121004,and 42077190)the Science and Technology Project of Shaoguan (No.210811164532141)+3 种基金the National Key R&D Program of China (2022YFC3700604)the Science and Technology Program of Guangzhou City (No.202201010400)the Fundamental Research Funds for the Central Universities (No.21622319)the Research Center of Low Carbon Economy for Guangzhou Region (No.22JNZS50).
文摘Emission characteristics of biogenic volatile organic compounds(BVOCs)from dominant tree species in the subtropical pristine forests of China are extremely limited.Here we conducted in situ field measurements of BVOCs emissions from representative mature evergreen trees by using dynamic branch enclosures at four altitude gradients(600-1690ma.s.l.)in the Nanling Mountains of southern China.Composition characteristics as well as seasonal and altitudinal variations were analyzed.Standardized emission rates and canopyscale emission factors were then calculated.Results showed that BVOCs emission intensities in the wet season were generally higher than those in the dry season.Monoterpenes were the dominant BVOCs emitted from most broad-leaved trees,accounting for over 70%of the total.Schima superba,Yushania basihirsuta and Altingia chinensis had relatively high emission intensities and secondary pollutant formation potentials.The localized emission factors of isoprene were comparable to the defaults in the Model of Emissions of Gases and Aerosols fromNature(MEGAN),while emission factors of monoterpenes and sesquiterpenes were 2 to 58 times of those in the model.Our results can be used to update the current BVOCs emission inventory in MEGAN,thereby reducing the uncertainties of BVOCs emission estimations in forested regions of southern China.
基金supported by Ningbo’s major scientific and technological breakthrough project“Research and Demonstration on the Technology of Collaborative Disposal of Secondary Ash in Typical Industrial Furnaces” (No.20212ZDYF020047)the central balance fund project“Research on Carbon Emission Accounting and Emission Reduction Potential Assessment for the Whole Life Cycle of Iron and Steel Industry” (No.2021-JY-07).
文摘China is the most important steel producer in the world,and its steel industry is one of themost carbon-intensive industries in China.Consequently,research on carbon emissions from the steel industry is crucial for China to achieve carbon neutrality and meet its sustainable global development goals.We constructed a carbon dioxide(CO_(2))emission model for China’s iron and steel industry froma life cycle perspective,conducted an empirical analysis based on data from2019,and calculated the CO_(2)emissions of the industry throughout its life cycle.Key emission reduction factors were identified using sensitivity analysis.The results demonstrated that the CO_(2)emission intensity of the steel industry was 2.33 ton CO_(2)/ton,and the production and manufacturing stages were the main sources of CO_(2)emissions,accounting for 89.84%of the total steel life-cycle emissions.Notably,fossil fuel combustion had the highest sensitivity to steel CO_(2)emissions,with a sensitivity coefficient of 0.68,reducing the amount of fossil fuel combustion by 20%and carbon emissions by 13.60%.The sensitivities of power structure optimization and scrap consumption were similar,while that of the transportation structure adjustment was the lowest,with a sensitivity coefficient of less than 0.1.Given the current strategic goals of peak carbon and carbon neutrality,it is in the best interest of the Chinese government to actively promote energy-saving and low-carbon technologies,increase the ratio of scrap steel to steelmaking,and build a new power system.
基金supported by the Humanities and Social Sciences Project of the Ministry of Education of the Peoples Republic(No.21YJCZH099)the National Natural Science Foundation of China(Nos.41401089 and 41741014)the Science and Technology Project of Sichuan Province(No.2023NSFSC1979).
文摘Majority of carbon emissions originate from fossil energy consumption,thus necessitating calculation and monitoring of carbon emissions from energy consumption.In this study,we utilized energy consumption data from Sichuan Province and Chongqing Municipality for the years 2000 to 2019 to estimate their statistical carbon emissions.We then employed nighttime light data to downscale and infer the spatial distribution of carbon emissions at the county level within the Chengdu-Chongqing urban agglomeration.Furthermore,we analyzed the spatial pattern of carbon emissions at the county level using the coefficient of variation and spatial autocorrelation,and we used the Geographically and Temporally Weighted Regression(GTWR)model to analyze the influencing factors of carbon emissions at this scale.The results of this study are as follows:(1)from 2000 to 2019,the overall carbon emissions in the Chengdu-Chongqing urban agglomeration showed an increasing trend followed by a decrease,with an average annual growth rate of 4.24%.However,in recent years,it has stabilized,and 2012 was the peak year for carbon emissions in the Chengdu-Chongqing urban agglomeration;(2)carbon emissions exhibited significant spatial clustering,with high-high clustering observed in the core urban areas of Chengdu and Chongqing and low-low clustering in the southern counties of the Chengdu-Chongqing urban agglomeration;(3)factors such as GDP,population(Pop),urbanization rate(Ur),and industrialization structure(Ic)all showed a significant influence on carbon emissions;(4)the spatial heterogeneity of each influencing factor was evident.
文摘Biliary tract cancer(BTC)is a group of heterogeneous sporadic diseases,including intrahepatic,hilar,and distal cholangiocarcinoma,as well as gallbladder cancer.BTC is characterized by high invasiveness and extremely poor prognosis,with a global increased incidence due to intrahepatic cholangiocarcinoma(ICC).The 18Ffludeoxyglucose positron emission tomography(PET)computed tomography(18F-FDG PET/CT)combines glucose metabolic information(reflecting the glycolytic activity of tumor cells)with anatomical structure to assess tumor metabolic heterogeneity,systemic metastasis,and molecular characteristics noninvasively,overcoming the limitations of traditional imaging in the detection of micrometastases and recurrent lesions.18F-FDG PET/CT offers critical insights in clinical staging,therapeutic evaluation,and prognostic prediction of BTC.This article reviews research progress in this field over the past decade,with a particular focus on the advances made in the last 3 years,which have not been adequately summarized and recognized.The research paradigm in this field is shifting from qualitative to quantitative studies,and there have been significant breakthroughs in using 18F-FDG PET/CT metabolic information to predict gene expression in ICC.Radiomics and deep learning techniques have been applied to ICC for prognostic prediction and differential diagnosis.Additionally,PET/magnetic resonance imaging is increasingly demonstrating its value in this field.
基金supported by the Key Research and Development Program in Shaanxi Province,China(No.2022ZDLSF07-05)the Fundamental Research Funds for the Central Universities,CHD(No.300102352901)。
文摘Carbon emissions resulting from energy consumption have become a pressing issue for governments worldwide.Accurate estimation of carbon emissions using satellite remote sensing data has become a crucial research problem.Previous studies relied on statistical regression models that failed to capture the complex nonlinear relationships between carbon emissions and characteristic variables.In this study,we propose a machine learning algorithm for carbon emissions,a Bayesian optimized XGboost regression model,using multi-year energy carbon emission data and nighttime lights(NTL)remote sensing data from Shaanxi Province,China.Our results demonstrate that the XGboost algorithm outperforms linear regression and four other machine learning models,with an R^(2)of 0.906 and RMSE of 5.687.We observe an annual increase in carbon emissions,with high-emission counties primarily concentrated in northern and central Shaanxi Province,displaying a shift from discrete,sporadic points to contiguous,extended spatial distribution.Spatial autocorrelation clustering reveals predominantly high-high and low-low clustering patterns,with economically developed counties showing high-emission clustering and economically relatively backward counties displaying low-emission clustering.Our findings show that the use of NTL data and the XGboost algorithm can estimate and predict carbon emissionsmore accurately and provide a complementary reference for satellite remote sensing image data to serve carbon emission monitoring and assessment.This research provides an important theoretical basis for formulating practical carbon emission reduction policies and contributes to the development of techniques for accurate carbon emission estimation using remote sensing data.
基金supported by the National Natural Science Foundation of China(Nos.42375171 and 42105157)the Interdisciplinary Research Project for Young Teachers of USTB(No.06600083)+1 种基金Energy Foundation(Nos.G-2109-33379 and G-2306-34754)the Fundamental Research Funds for the Central Universities(No.06500166).
文摘Civil aviation is one of the industries facing the greatest challenge in reaching carbon neutrality by the middle of this century,and this sector also contributes to adverse impacts on the regional air quality and human health.China exhibits the second highest air passenger turnover worldwide.Our understanding of civil aviation emissionsmust be urgently enhanced,and themitigation potential should be explored.In this study,on the basis of real domestic flight information for 2019,we built a greenhouse gas and air pollution emission inventory for the civil aviation sector in China with the fuel flowmethod based on the cruise and other phases.We thoroughly analyzed emissions by region,aircraft and engine types,and aircraft age,based on which we designed four measures to evaluate the abatement potential.We found that the hydrocarbon(HC),CO,NO_(x),SO_(2),particulate matter(PM)and CO_(2)emissions in 2019 reached 79.9 kt(95%CI[51.6–114.5]),176.3 kt(95%CI[114.5–248.2]),304.2 kt(95%CI[203.4–420.7]),23.2 kt(95%CI[14.2–33.7]),1.0 kt(95%CI[0.61–1.44])and 87.0 Mt(95%CI[57.4–119.6]),respectively.The cruise phase was the major emission phase,accounting for 67%-87%of the total pollutant emissions.If four measures were jointly implemented,the HC,CO,NO_(x),SO_(2),PM and CO_(2)emissions could be reduced by 61%,54%,55%,45%,32%and 38%,respectively.Utilizing lower-emission aircraft and switching travel modes could substantially reduce civil aviation emissions in China.
基金supported by the Special Fund for Science and Technology Innovation Strategy of Guangdong Province,China(2022660500250009604)。
文摘Methane contributes to global warming,and livestock is one of the sources of methane production.However,methane emission studies using bibliometric tools in livestock are lacking.Given the negative impact of climate change on the ecosystem and the rise in methane emissions,it is essential to conduct a bibliometrics study to provide an overview and research trends.We used the Bibliometrix package and VOSviewer to decipher bibliometric indices for methane emissions in cattle farms(MECF).Current dataset were collected from the Web of Science(Core Collection)database,and 8,998 publications were analyzed.The most co-occurring keywords scientists preferred were methane(1,528),greenhouse gas(443),methane emissions(440),and cattle(369).Methane was the most frequently used keyword in the published scientific literature.Thematic evolution of research themes and trend results highlighted carbon dioxide,methane,dairy cattle,cattle,and risk factors during 1999–2017.Chinese Academy of Sciences ranked on top with 485 publications,followed by Agriculture&Agri-Food Canada,University of Colorado,National Oceanic and Atmospheric Administration,and Aarhus University.Chinese Academy of Sciences was also the most cited organization,followed by the University of Colorado,Agriculture&Agri-Food Canada,National Oceanic and Atmospheric Administration,and United States Geological Survey.Source analysis showed that the Science of the Total Environment was cited with the highest total link strength.Science of the Total Environment ranked first in source core 1 with 290 citation frequencies,followed by Journal of Dairy Science with 223 citation frequencies.Currently,no bibliometric study has been conducted on MECF,and to fill this knowledge gap,we carried out this study to highlight methane emissions in cattle farms,aiming at a climate change perspective.In this regard,we focused on the research productivity of countries authors,journals and institutions,co-occurrence of keywords,evolution of research trends,and collaborative networking.Based on relevance degree of centrality,methane emissions and greenhouse gases appeared as basic themes,cattle,and dairy cattle appeared as emerging/declining themes,whereas,methane,greenhouse gas and nitrous oxide appeared to fall amongst basic and motor themes.On the other hand,beef cattle,rumen and dairy cow seem to be between motor and niche themes,and risk factors lie in niche themes.The present bibliometric analysis provides research progress on methane emissions in cattle farms.Current findings may provide a framework for understanding research trends and themes in MECF research.
基金supported by the Youth Innovation Program of the Chinese Academy of Agricultural Sciences(Y2022QC10)the Agricultural Science and Technology Innovation Program,China(CAAS-ASTIP-2023-IFR-03,CAAS-IFR-ZDRW202302 and CAAS-IFR-ZDRW202404)the Basal Research Fund of the Institute of Feed Research of Chinese Academy of Agricultural Sciences(1610382024009)。
文摘Cutting farming-related methane emissions from ruminants is critical in the battle against climate change.Since scientists initially investigated the potential of marine macroalgae to reduce methane emissions,using seaweeds as an anti-methanogenic feed additive has become prevailing in recent years.Asparagopsis taxiformis is the preferred species because it contains a relatively higher concentration of bromoform.As a type of halogenated methane analogue,bromoform contained in A.taxiformis can specifically inhibit the activity of coenzyme M methyltransferase,thereby blocking the ruminal methanogenesis.However,bromoform is a potential toxin and ozone-depleting substance.In response,current research focuses on the effects of bromoform-enriched seaweed supplementation on ruminant productivity and safety,as well as the impact of large-scale cultivation of seaweeds on the atmospheric environment.The current research on seaweed still needs to be improved,especially in developing more species with low bromoform content,such as Bonnemaisonia hamifera,Dictyota bartayresii,and Cystoseira trinodis.Otherwise,seaweed is rich in bioactive substances and exhibits antibacterial,anti-inflammatory,and other physiological properties,but research on the role of these bioactive compounds in methane emissions is lacking.It is worthy of deeper investigation to identify more potential bioactive compounds.As a new focus of attention,seaweed has attracted the interest of many scientists.Nevertheless,seaweed still faces some challenges as a feed additive to ruminants,such as the residues of heavy metals(iodine and bromine)and bromoform in milk or meat,as well as the establishment of a supply chain for seaweed cultivation,preservation,and processing.We have concluded that the methane-reducing efficacy of seaweed is indisputable.However,its application as a commercial feed additive is still influenced by factors such as safety,costs,policy incentives,and regulations.
基金supported by the National Key R&D Program of China(No.2023YFC3707201)the National Natural Science Foundation of China(No.52320105003)+1 种基金the Informatization Plan of Chinese Academy of Sciences(No.CAS-WX2023PY-0103)the Fundamental Research Funds for the Central Universities(No.E3ET1803).
文摘Nitrous oxide(N_(2)O),as an important gas affecting climate warming,is attracting attention from allwalks of life.This reviewaddresses N_(2)O emissions status in the adipic acid industry,a significant industrial greenhouse gas source.It elucidates the N_(2)O emission mechanism and influencing factors in adipic acid production.It extensively evaluates N_(2)O emission accounting methods,including Intergovernmental Panel on Climate Change(IPCC)Guidelines,World Resources Institute(WRI)Protocol,and others.While the IPCC emission factor method offers simplicity and comparability,it may lack precision for facilities with advanced emission reduction measures.To address this,a combined modeling and monitoring approach is advocated.It scrutinizes modeling methods(statistical techniques,Greenhouse Gas and Air Pollution Interactions and Synergies,and Life-cycle Assessment)and highlights their reliance on specific data and perspectives.It emphasizes the growing importance of on-site monitoring with mid-IR technology.Additionally,it underscores the potential of aircraft-based and satellite remote sensing for comprehensive N_(2)O emissions data.The reviewalso highlights recent advancements in emission mitigation,particularly in adipic acid synthesis techniques,showing substantial potential for N_(2)O reduction.Innovative paradigms and strategies for N_(2)O mitigation in the adipic acid industry are presented,with a focus on achieving nitrogen oxides(NO_(x))-free production.These approaches hold promise for emission reduction,given the high removal efficiency in plant end-of-treatment processes.Various accounting methods,monitoring techniques,and mitigation strategies were integrated and analyzed to provides a comprehensive overview of N_(2)O emissions in the adipic acid industry,with the aim of guiding future research and policy initiatives.
基金supported by the National Natural Science Foundation of China(Nos.U19A2044,42105132,42030609,41975037,and 42105133)the National Key Research and Development Program of China(No.2022YFC3703502)+1 种基金the Plan for Anhui Major Provincial Science&Technology Project(No.202203a07020003)Hefei Ecological Environment Bureau Project(No.2020BFFFD01804).
文摘As a significant city in the Yangtze River Delta regions,Hefei has experienced rapid changes in the sources of air pollution due to its high-speed economic development and urban expansion.However,there has been limited research in recent years on the spatial-temporal distribution and emission of its atmospheric pollutants.To address this,this study conducted mobile observations of urban roads using the Mobile-DOAS instrument from June 2021 to May 2022.The monitoring results exhibit a favourable consistent with TROPOMI satellite data and ground monitoring station data.Temporally,there were pronounced seasonal variations in air pollutants.Spatially,high concentration of HCHO and NO_(2)were closely associated with traffic congestion on roadways,while heightened SO_(2)levels were attributed to winter heating and industrial emissions.The study also revealed that with the implementation of road policies,the average vehicle speed increased by 95.4%,while the NO concentration decreased by 54.4%.In the estimation of urban NO_(x)emission flux,it was observed that in temporal terms,compared with inventory data,the emissions calculated viamobile measurements exhibitedmore distinct seasonal patterns,with the highest emission rate of 349 g/sec in winter and the lowest of 142 g/sec in summer.In spatial terms,the significant difference in emissions between the inner and outer ring roads also suggests the presence of the city’s primary NO_(x)emission sources in the area between these two rings.This study offers data support for formulating the next phase of air pollution control measures in urban areas.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.U20A20266 and 12302503)Scientific and technological research projects in Sichuan province(Grant No.2024NSFSC0973).
文摘The loaded rock experiences multiple stages of deformation.It starts with the formation of microcracks at low stresses(crack initiation,CI)and then transitions into unstable crack propagation(crack damage,CD)near the ultimate strength.In this study,both the acoustic emission method(AEM)and the ultrasonic testing method(UTM)were used to examine the characteristics of AE parameters(b-value,peak frequency,frequency-band energy ratio,and fractal dimension)and ultrasonic(ULT)properties(velocity,amplitude,energy attenuation,and scattering attenuation)of bedded shale at CI,CD,and ultimate strength.The comparison involved analyzing the strain-based method(SBM),AEM,and UTM to determine the thresholds for damage stress.A fuzzy comprehensive evaluation model(FCEM)was created to describe the damage thresholds and hazard assessment.The results indicate that the optimal AE and ULT parameters for identifying CI and CD stress are ringing count,ultrasonic amplitude,energy attenuation,and scattering attenuation of the S-wave.Besides,damage thresholds were detected earlier by AE monitoring,ranging from 3 MPa to 10 MPa.CI and CD identified by UTM occurred later than SBM and AEM,and were in the range of 12 MPa.The b-value,peak frequency,energy ratio in the low-frequency band(0e62.5 kHz),correlation dimension,and sandbox dimension showed low values at the peak stress,while the energy ratio in a moderate-frequency band(187.5e281.25 kHz)and amplitude showed high values.The successful application of FCEM to laboratory testing of shales has demonstrated its ability to quantitatively identify AE/ULT precursors of seismic hazards associated with rock failure.
基金supported by the top-level design of the National Natural Science Foundation of China(NSFC)Major Project“Realization of optimal carbon neutral pathway and coupling of multi-scale interaction patterns of natural-social systems in China”(42341202)the Basic Scientific Research Fund of the Chinese Academy of Meteorological Sciences(2021Z014)。
文摘This paper proposes that China,under the challenge of balancing its development and security,can aim for the Paris Agreement's goal to limit global warming to no more than 2℃by actively seeking carbonpeak and carbon-neutrality pathways that align with China's national conditions,rather than following the idealized path toward the 1.5℃target by initially relying on extensive negative-emission technologies such as direct air carbon capture and storage(DACCS).This work suggests that pursuing a 1.5℃target is increasingly less feasible for China,as it would potentially incur 3–4 times the cost of pursuing the 2℃target.With China being likely to achieve a peak in its emissions around 2028,at about 12.8 billion tonnes of anthropogenic carbon dioxide(CO_(2)),and become carbon neutral,projected global warming levels may be less severe after the 2050s than previously estimated.This could reduce the risk potential of climate tipping points and extreme events,especially considering that the other two major carbon emitters in the world(Europe and North America)have already passed their carbon peaks.While natural carbon sinks will contribute to China's carbon neutrality efforts,they are not expected to be decisive in the transition stages.This research also addresses the growing focus on climate overshoot,tipping points,extreme events,loss and damage,and methane reductions in international climate cooperation,emphasizing the need to balance these issues with China's development,security,and fairness considerations.China's pursuit of carbon neutrality will have significant implications for global emissions scenarios,warming levels,and extreme event projections,as well as for climate change hotspots of international concern,such as climate tipping points,the climate crisis,and the notion that the world has moved from a warming to a boiling era.Possible research recommendations for global emissions scenarios based on China's 2℃target pathway are also summarized.
基金supported by the Energy Foundation(No.G-2203-33693).
文摘To understand the smoke level and NO_(x)emission characteristics of in-use construction machinery in Beijing,we selected 905 construction machines in Beijing from August 2022 to April 2023 to monitor the emission level of smoke and NO_(x).The exhaust smoke level and excessive emission situation of different machinery types were identified,and their NO_(x)emission levels were monitored according to the free acceleration method.We investigated the correlation of NO_(x)and smoke emission,and proposed suggestions for controlling pollution discharge from construction machinery in the future.The results show that the exhaust smoke level was 0–2.62 m^(−1),followed a log-normal distribution(μ=-1.73,δ=1.09,R^(2)=0.99),with a 5.64%exceedance rate.Differenceswere observed amongmachinery types,with low-power engine forklifts showing higher smoke levels.The NO_(x)emission range was 71–1516 ppm,followed a normal distribution(μ=565.54,δ=309.51,R^(2)=0.83).Differences among machinery types were relatively small.Engine rated net power had the most significant impact on NO_(x)emissions.Thus,NO_(x)emissions from construction machinery need further attention.Furthermore,we found a weak negative correlation(p<0.05)between the emission level of smoke and NO_(x),that is the synergic emission reduction effect is poor,emphasizing the need for NO_(x)emission limits.In the future,the oversight in Beijing should prioritize phasing out ChinaⅠand ChinaⅡmachinery,and monitor emissions from highpower engine ChinaⅢmachinery.
