Oxidative potential(OP)can be used as an indicator of the health risks of particulate matter in the air.To study the variation and sources of OP,we conducted an observation of PM_(2.5) in a megacity in southern China ...Oxidative potential(OP)can be used as an indicator of the health risks of particulate matter in the air.To study the variation and sources of OP,we conducted an observation of PM_(2.5) in a megacity in southern China in winter and spring of 2021.The results show that the average concentration of PM_(2.5) decreased by 47%from winter to spring,while volume-normalized and mass-normalized OP(i.e.,OP_(v) and OP_(m))increased by 6%and 69%,respectively.It suggests that the decline of PM_(2.5) may not necessarily decrease the health risks and the intrinsic toxicity of PM_(2.5).Variations of OP_(v) and OP_(m) among different periods were related to the different source contributions and environmental conditions.The positive matrix factorization model was used to identify the major sources of OP_(v).OP_(v) was mainly contributed by biomass burning/industrial emissions(29%),soil/road dust(20%),secondary sulfate(14%),and coal combustion(13%)in winter.Different major sources were resolved to be secondary sulfate(36%),biological sources(21%),and marine vessels(20%)in spring,presenting the substantial contribution of biological sources.The analysis shows strong associations between OP_(v) and both live and dead bacteria,further confirming the important contribution of bioaerosols to the enhancement of OP.This study highlights the importance of understanding OP in ambient PM_(2.5) in terms of public health impact and provides a new insight into the biological contribution to OP.展开更多
The Early Cambrian Yuertusi Formation(Є_(1)y)in the Tarim Basin of China deposits a continuously developed suite of organic-rich black mudstones,which constitute an important source of oil and gas reservoirs in the Pa...The Early Cambrian Yuertusi Formation(Є_(1)y)in the Tarim Basin of China deposits a continuously developed suite of organic-rich black mudstones,which constitute an important source of oil and gas reservoirs in the Paleozoic.However,its hydrocarbon generation and evolution characteristics and resource potential have long been constrained by deeply buried strata and previous research.In this paper,based on the newly obtained ultra-deep well drilling data,the hydrocarbon generation and expulsion model ofЄ_(1)y shale was established by using data-driven Monte Carlo simulation,upon which the hydrocarbon generation,expulsion,and retention amounts were calculated by using the diagenetic method.The research indicates that theЄ_(1)y shale reaches the hydrocarbon generation and expulsion threshold at equivalent vitrinite reflectances of 0.46%and 0.72%,respectively.The cumulative hydrocarbon generation is 68.88×10^(10)t,the cumulative hydrocarbon expulsion is 35.59×10^(10)t,and the cumulative residual hydrocarbon is 33.29×10^(10)t.This paper systematically and quantitatively calculates the hydrocarbon expulsion at various key geological periods for theЄ_(1)y source rocks in the study area for the first time,more precisely confirming that the black shale of theЄ_(1)y is the most significant source rock contributing to the marine oil and gas resources in the Tarim Basin,filling the gap in hydrocarbon expulsion calculation in the study area,and providing an important basis for the formation and distribution of Paleozoic hydrocarbon reservoirs.The prospect of deep ultra-deep oil and gas exploration in the Tarim Basin is promising.Especially,the large area of dolomite reservoirs under the Cambrian salt and source rock interiors are the key breakthrough targets for the next exploration in the Tarim Basin.展开更多
The toxicity of PM_(2.5)does not necessarily change synchronously with its mass concentration.In this study,the chemical composition(carbonaceous species,water-soluble ions,and metals)and oxidative potential(dithiothr...The toxicity of PM_(2.5)does not necessarily change synchronously with its mass concentration.In this study,the chemical composition(carbonaceous species,water-soluble ions,and metals)and oxidative potential(dithiothreitol assay,DTT)of PM_(2.5)were investigated in 2017/2018 and 2022 in Xiamen,China.The decrease rate of volume-normalized DTT(DTTv)(38%)was lower than that of PM_(2.5)(55%)between the two sampling periods.However,the mass-normalized DTT(DTTm)increased by 44%.Clear seasonal patterns with higher levels in winter were found for PM_(2.5),most chemical constituents and DTTv but not for DTTm.The large decrease in DTT activity(84%−92%)after the addition of EDTA suggested that watersoluble metals were the main contributors to DTT in Xiamen.The increased gap between the reconstructed and measured DTTv and the stronger correlations between the reconstructed/measured DTT ratio and carbonaceous species in 2022were observed.The decrease rates of the hazard index(32.5%)and lifetime cancer risk(9.1%)differed from those of PM_(2.5)and DTTv due to their different main contributors.The PMF-MLR model showed that the contributions(nmol/(min·m^(3)))of vehicle emission,coal+biomass burning,ship emission and secondary aerosol to DTTv in 2022 decreased by 63.0%,65.2%,66.5%,and 22.2%,respectively,compared to those in 2017/2018,which was consistent with the emission reduction of vehicle exhaust and coal consumption,the adoption of low-sulfur fuel oil used on board ships and the reduced production of WSOC.However,the contributions of dust+sea salt and industrial emission increased.展开更多
This study tracked the characteristics of atmospheric wet deposition of the toxic element arsenic(As)at both urban(Guangzhou(GZ))and forested(Dinghushan Natural Reserve(DHS))sites within the Pearl River Delta(PRD)regi...This study tracked the characteristics of atmospheric wet deposition of the toxic element arsenic(As)at both urban(Guangzhou(GZ))and forested(Dinghushan Natural Reserve(DHS))sites within the Pearl River Delta(PRD)region between 2016 and 2019,examining its correlation with rainfall patterns.Additionally,by employing backward trajectory analysis and the potential source contribution function(PSCF)in conjunction with pertinent emission inventories,we pinpointed the main pathways of atmospheric arsenic transport and evaluated the emission contributions from priority source areas.The study revealed that the atmospheric arsenic wet deposition fluxes at the GZ and DHS sites exhibited a trend of increase followed by a decrease over the four-year period.Wet season deposition fluxes were more than triple those of the dry season,with urban site showing a difference of over four times.Notably,wet season As deposition at both sites was predominantly affected by heavy rainfall from marine air masses,constituting 31%of the total deposition.The predominant trajectory directions contributing to arsenic deposition at GZ and DHS were northeast(55%)and south(53%),respectively.The primary source areas for both sites were largely outside the PRD region,with the GZ site having 80%to 95%of its source area in the non-PRD region,compared to 69%to 88%at the DHS site.Furthermore,non-PRD areas contributed approximately 65%to arsenic emissions for both sites,with the industrial sector being the dominant emission source,exceeding 97%of the total emissions.展开更多
Black carbon (BC) aerosols are considered key factors that contribute to rapid climate warming and ice melt in the Arctic region.However,compared with long-term observations from land-based stations,observational data...Black carbon (BC) aerosols are considered key factors that contribute to rapid climate warming and ice melt in the Arctic region.However,compared with long-term observations from land-based stations,observational data over the Arctic Ocean remain relatively scarce.Four Arctic scientific expeditions were conducted in the summer and early autumn of 2010,2012,2016,and 2018 via the Chinese research vessel Xue Long,during which the BC concentrations along the routes were measured via light absorption methods.In this work,the spatiotemporal distribution characteristics of BC over the Arctic Ocean were examined on the basis of these observations.The potential sources of BC along the various routes were analyzed via the weighted potential source contribution function and weighted concentrationweighted trajectory methods of the hybrid single-particle Lagrangian integrated trajectory model in conjunction with Arctic transport potential climate model simulations.The analysis results indicated that wildfires in the western Aleutian Islands,Siberia,and Far East regions were the primary contributors to the BC aerosol concentration observed along the Arctic expedition routes in summer,identifying these regions as major potential source areas.展开更多
Inhalation of atmospheric PM_(2.5)can induce the generation of excessive reactive oxygen species(ROS)in human alveoli,triggering local and systemic inflammation,which can directly or indirectly result in respiratory a...Inhalation of atmospheric PM_(2.5)can induce the generation of excessive reactive oxygen species(ROS)in human alveoli,triggering local and systemic inflammation,which can directly or indirectly result in respiratory and cardiovascular diseases.In this study,we assessed the oxidative potential(OP)of fresh and O_(3)-aged PM_(2.5)particles from various urban and rural emission sources using the dithiothreitol(DTT)method.Our results revealed variations in the OP of fresh PM_(2.5)among different emission sources,with biomass burning sources exhibiting the highest OP,followed by industrial areas,vehicular emissions,cooking emissions,and suburban areas,respectively.Water-soluble organics and transition metals might potentially exert significant influence on particle OP.O_(3)aging notably decreased the OP of PM_(2.5)particles,possibly due to the oxidation of highly DTT-active components into low redox-active small molecules.Moreover,the evolution of OP in different PM_(2.5)components,including methanol-soluble and insoluble fractions,exhibited distinct responses to O_(3)aging for source-oriented PM_(2.5).Additionally,differences in chemical composition between fresh and aged PM_(2.5)were further elucidated through measurements of component-dependent hygroscopic behaviors and phase transitions.This study systematically delineates variances in the toxic potential of fresh and O_(3)-aged PM_(2.5)from various anthropogenic sources.The findings highlight the intrinsic compositional dependence of particle OP and provide essential insights for assessing the health effects of source-oriented PM_(2.5),as well as for formulating human health protection policies.展开更多
Carbonyl compounds play a pivotal role in the formation of secondary pollutants such as O_(3) and SOA,signifi-cantly impacting air quality and human health.This study extended the observation period compared to previo...Carbonyl compounds play a pivotal role in the formation of secondary pollutants such as O_(3) and SOA,signifi-cantly impacting air quality and human health.This study extended the observation period compared to previous research,providing a long-term perspective on carbonyl compound variations and their environmental implica-tions.Atmospheric observations were conducted at Beijing(BJ)and Xianghe(XH)during the summer and winter months of 2018,2019,and 2023 to study the sources and impacts of carbonyl compounds in typical urban areas and peri‑urban areas.Notably,concentrations in the summer of 2023 increased compared to 2018 and 2019.The predominant carbonyl compounds—formaldehyde,acetaldehyde,and acetone—accounted for over 60%of the total.The mean values of OFP in BJ ranged from 18.55 to 58.61μg/m3,lower than those in XH(29.82 to 65.48μg/m3),with formaldehyde and acetaldehyde contributing over 80%of the total.SOAP exhibited a similar pattern,with values in XH(69.21 to 508.55μg/m3)significantly exceeding those in BJ(34.47 to 159.78μg/m3).The PMF model highlighted vehicle exhaust,secondary pollution,and biomass combustion as major sources of carbonyl compounds,emphasizing differences in source contributions between the two regions.This study’s com-parative analysis over different years and locations provides new insights into the dynamic changes in carbonyl compounds and their environmental importance.These results not only reinforce the importance of carbonyl compounds regulation but also offer a valuable reference for evaluating and refining emission control strategies during this period.展开更多
Nitrogen(N)and phosphorus(P)are essential nutrients and can significantly impact primary productivity of the ecosystem causing water environmental problems.However,their cycling mechanisms are not well understood in a...Nitrogen(N)and phosphorus(P)are essential nutrients and can significantly impact primary productivity of the ecosystem causing water environmental problems.However,their cycling mechanisms are not well understood in alpine mountains with climate change.Hence,94 samples of river water were collected from 2018 to 2020 in the headwaters of the Shule River Basin to assess the nutrients spatiotemporal distribution and combined ap-proach of water quality index to assess water quality and potential sources.The findings depict that high nutrient concentrations were found to coincide with snowmelt and glacial meltwater and rainfall recharge periods,while total flux peaked from June to September due to increased runoff.Notably,total nitrogen(TN)concentrations were significantly higher near the town,primarily attributed to the replenishment of nitrate(NO_(3)^(‒)-N)from live-stock manure.The high total P(TP)was near the glacier,which was attributed to the transportation of glacial sediments into the river,and pH was another critical factor.N was the primary nutrient limiting factor for the growth of phytoplankton in river water.Although the migration and transport of nutrients have altered with climate change,river water quality is good in alpine mountains based on an overall evaluation.These findings contribute to enriching nutrient datasets and highlight the importance of water resource management and water quality assessment in sensitive and fragile alpine mountains.展开更多
Carboniferous source rocks identified by drilling in Santanghu （三塘湖） Basin were evaluated for their source potential, employing organic geochemistry and RockEval pyrolysis. The organic matter origin and depositio...Carboniferous source rocks identified by drilling in Santanghu （三塘湖） Basin were evaluated for their source potential, employing organic geochemistry and RockEval pyrolysis. The organic matter origin and depositional environment of these samples were also determined through biomarker analysis. Most of the Carboniferous source rocks in Santanghu Basin are characterised by high values of total organic carbon （TOC） content and high extractable organic matter content and hydrocarbon yields, indicating that they are organicrich source rocks with high oil generative potential. The organic matter is predominantly Type I and Type II kerogen with a minor contribution of Type III kerogen, as demonstrated by its pyrolysis parameters and carbon isotope values. According to Ro （%） and T max values, most of the studied samples are at earlyto middle-thermal mature stage; only a few of the samples are at a highly mature stage （past peak oil generation）. The biomarker analysis reveals a dominance of algal/bacterial organic matter input, with a minor contribution of land plant material. Pr/Ph ratio supports a suboxic depositional condition, consistent with a neritic or marine-continental alternating environment proposed by predecessor.展开更多
A distinctive kind of organic carbon aerosol that could absorb ultraviolet-visible radiation is called brown carbon(Br C),which has an important positive influence on radiative budget and climate change.In this work,w...A distinctive kind of organic carbon aerosol that could absorb ultraviolet-visible radiation is called brown carbon(Br C),which has an important positive influence on radiative budget and climate change.In this work,we reported the absorption properties and potential source of Br C based on a seven-wavelength aethalometer in the winter of 2018–2019 at an urban site of Sanmenxia in Fenwei Plain in central China.Specifically,the mean value of Br C absorption coefficient was 59.6±36.0 Mm^(-1) at 370 nm and contributed 37.7%to total absorption,which made a significant impact on visibility and regional environment.Absorption coefficients of Br C showed double-peak pattern,and Br C had shown small fluctuations under haze days compared with clean days.As for the sources of Br C,Br C absorption coefficients expressed strong correlations with element carbon aerosols and primary organic carbon aerosols,indicating that most of Br C originated from primary emissions.The linear correlations between trace metal elements(K,As,Fe,Mn,Zn,and Pb)and Br C absorption coefficients further referred that the major sources of Br C were primary emissions,like coal burning,biomass burning,and vehicle emissions.The moderate relationship between Br C absorption coefficients and secondary organic aerosols suggested that secondary production of Br C also played an important role.The 120 hr backward air mass trajectories analysis and concentration-weighted trajectories analysis were also used to investigate potential sources of Br C in and around this area,which inferred most parts of Br C were derived from local emissions.展开更多
The chemical characteristics,oxidative potential,and sources of PM_(2.5)were analyzed at the urban sites of Lahore and Peshawar,Pakistan in February 2019.Carbonaceous species,water soluble ions,and metal elements were...The chemical characteristics,oxidative potential,and sources of PM_(2.5)were analyzed at the urban sites of Lahore and Peshawar,Pakistan in February 2019.Carbonaceous species,water soluble ions,and metal elements were measured to investigate the chemical composition and sources of PM_(2.5).The dithiothreitol(DTT)consumption rate was measured to evaluate the oxidative potential of PM_(2.5).Both cities showed a high exposure risk of PM_(2.5)regarding its oxidative potential(DTT v).Carbonaceous and some of the elemental species of PM_(2.5)correlated well with DTT v in both Lahore and Peshawar.Besides,the DTT v of PM_(2.5)in Lahore showed significant positive correlation with most of the measured water soluble ions,however,ions were DTT-inactive in Peshawar.Due to the higher proportions of carbonaceous species and metal elements,Peshawar showed higher mass-normalized DTT activity of PM_(2.5)compared to Lahore although the average PM_(2.5)concentration in Peshawar was lower.The high concentrations of toxic metals also posed serious non-carcinogenic and carcinogenic risks to the residents of both cities.Principle component analysis coupled with multiple linear regression was applied to investigate different source contributions to PM_(2.5)and its oxidative potential.Mixed sources of traffic and road dust resuspension and coal combustion,direct vehicle emission,and biomass burning and formation of secondary aerosol were identified as the major sources of PM_(2.5)in both cities.The findings of this study provide important data for evaluation of the potential health risks of PM_(2.5)and for formulation of efficient control strategies in major cities of Pakistan.展开更多
Magnitude and distance of major potential source are needed in order to determine duration time of artificial ground motion and to determine the type of response spectrum (near field or far field) when using the seism...Magnitude and distance of major potential source are needed in order to determine duration time of artificial ground motion and to determine the type of response spectrum (near field or far field) when using the seismic intensity zonation map. The magnitude probabilistic distribution function of seismic belt and the magnitude and space joint distribution function for given intensity of the site in a potential Source are provided. Then the basicformula of calculating expected magnitude and expected distance are developed. Several examples for calculating expected magnitude and expected distance in northern China are discussed. These results show that expected magnitude and expected distance are related not only to geometry of potential source and magnitude but also to the intensity of the site with certain exceeding probability.展开更多
This study attempts to identify the dominant transport pathways,potential source areas,and their seasonal variation at sites with high inorganic nitrogen(IN)wet deposition flux in southern China.This is a long-term st...This study attempts to identify the dominant transport pathways,potential source areas,and their seasonal variation at sites with high inorganic nitrogen(IN)wet deposition flux in southern China.This is a long-term study(2010-2017)based on continuous deposition measurements at the Guangzhou urban site(GZ)and the Dinghushan Natural Reserve site(DHS)located in the Pearl River Delta(PRD)region.A dataset on monthly IN concentration in precipitation and wet deposition flux were provided.The average annual fluxes measured at both sites(GZ:33.04±9.52,DHS:20.52±10.22 kg N/(ha·year))were higher,while the ratios of reduced to oxidized N(GZ:1.19±0.77,DHS:1.25±0.84)were lower compared with the national mean level and the previous reported level throughout the PRD region.The dominant pathways were not always consistent with the highest proportional trajectory clusters.The transport pathways contributing most of deposition were identified in the north and northnortheast in the dry season and in the east-southeast,east,and south-southwest in the wet season.A weighted potential source contribution function(WPSCF)value>0.3 was determined reasonably to define the potential source area.Emission within the PRD region contributed the majority(≥95%at both sites)of the IN deposition in the wet season,while the contribution outside the region increased significantly in the dry season(GZ:27.86%,DHS:95.26%).Our results could help create more effective policy to control precursor emissions for IN fluxes,enabling reduction of the ecological risks due to excessive nitrogen.展开更多
Kerogen types exert a decisive effect on the onset and capacity of hydrocarbon generation of source rocks.Lacustrine source rocks in the Liaohe Western Depression are characterized by thick deposition,high total organ...Kerogen types exert a decisive effect on the onset and capacity of hydrocarbon generation of source rocks.Lacustrine source rocks in the Liaohe Western Depression are characterized by thick deposition,high total organic carbon(TOC)content,various kerogen types,and a wide range of thermal maturity.Consequently,their hydrocarbon generation potential and resource estimation can be misinterpreted.In this study,geochemical tests,numerical analysis,hydrocarbon generation kinetics,and basin modeling were integrated to investigate the differential effects of kerogen types on the hydrocarbon generation potential of lacustrine source rocks.Optimized hydrocarbon generation and expulsion(HGE)models of different kerogen types were established quantitatively upon abundant Rock-Eval/TOC/vitrinite reflectance(R_(o))datasets.Three sets of good-excellent source rocks deposited in the fourth(Es4),third(Es3),and first(Es1)members of Paleogene Shahejie Formation,are predominantly types I-II_(1),II_(1)-II_(2),and II-III,respectively.The activation energy of types I-II_(2)kerogen is concentrated(180-230 kcal/mol),whereas that of type III kerogen is widely distributed(150-280 kcal/mol).The original hydrocarbon generation potentials of types I,II_(1),II_(2),and III kerogens are 790,510,270,and 85 mg/g TOC,respectively.The Ro values of the hydrocarbon generation threshold for type I-III source rocks gradually increase from 0.42%to 0.74%,and Ro values of the hydrocarbon expulsion threshold increase from 0.49%to 0.87%.Types I and II_(1)source rocks are characterized by earlier hydrocarbon generation,more rapid hydrocarbon expulsion,and narrower hydrocarbon generation windows than types II_(2)and III source rocks.The kerogen types also affect the HGE history and resource potential.Three types(conventional,tight,and shale oil/gas)and three levels(realistic,expected,and prospective)of hydrocarbon resources of different members in the Liaohe Western Depression are evaluated.Findings suggest that the Es3 member has considerable conventional and unconventional hydrocarbon resources.This study can quantitatively characterize the hydrocarbon generation potential of source rocks with different kerogen types,and facilitate a quick and accurate assessment of hydrocarbon resources,providing strategies for future oil and gas exploration.展开更多
The lower Tertiary Eh3 is divided into two sections： the upper members of Eh3 and the lower members of Eh3 in the Biyang Depression. The first section is generally regarded as a key target of oil and gas exploration,...The lower Tertiary Eh3 is divided into two sections： the upper members of Eh3 and the lower members of Eh3 in the Biyang Depression. The first section is generally regarded as a key target of oil and gas exploration, but the resource potential of the lower members of Eh3 has been neglected. We have obtained new knowledge about Eh3 from comprehensive geological research. The lower members of Eh3 are high-quality and main source rocks, which have good oil and gas resource potential. This is a new direction for oil and gas exploration. The geochemistry characteristics of source rocks of the lower members of Eh3 in the lower Tertiary of the Biyang Depression were analyzed in detail. A basin modeling method was applied to hydrocarbon generation of the lower and upper members of Eh3 source rocks, the oil and gas resource potential was comparatively analyzed, and then favorable tectonic zones were pointed out. In the lower members of Eh3, a set of semi-deep lake to deep lake high-quality source rocks occurs rich in algae organisms, mainly of type II1, with a high abundance of organic matter. Most of the source rocks are just in the peak stage of hydrocarbon generation, which is a favorable foundation for forming abundant oil and gas resources in the Biyang Depression. The comparative analysis of the hydrocarbon- generation quantities between lower and upper members of the Eh3 source rocks shows that the lower members of Eh3 have good oil and gas resource potential, and the hydrocarbon-generation quantity accounts for 51% of the total in Eh3. Specifically, the oil-generating quantity accounts for 50% of the total and the gas-generating quantity accounts for two thirds of the total. Therefore, source rocks in the lower members of Eh3 of the Biyang Depression have good oil and gas resource potential, which is a key factor for future deep oil and gas exploration.展开更多
Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haiko...Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou,China.The results showed that the annual average concentration of total VOCs(TVOCs)was 11.4 ppb V,and the composition was dominated by alkanes(8.2 ppb V,71.4%)and alkenes(1.3 ppb V,20.5%).The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening.The greatest contribution to ozone formation potential(OFP)was made by alkenes(51.6%),followed by alkanes(27.2%).The concentrations of VOCs and nitrogen dioxide(NO_(2))in spring and summer were low,and it was difficult to generate high ozone(O_(3))concentrations through photochemical reactions.The significant increase in O_(3)concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast.Traffic sources(40.1%),industrial sources(19.4%),combustion sources(18.6%),solvent usage sources(15.5%)and plant sources(6.4%)were identified as major sources of VOCs through the positive matrix factorization(PMF)model.The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function(PSCF)and concentration-weighted trajectory(CWT)models.Overall,the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport,and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou,thereby reducing the generation of O_(3).展开更多
From the outcrops in the Yaomoshan and Hongyanchi sections, oil shales, deep dark mudstones or black mudstones with better organic richness were found. Through the analysis of the samples in the organic petrology meth...From the outcrops in the Yaomoshan and Hongyanchi sections, oil shales, deep dark mudstones or black mudstones with better organic richness were found. Through the analysis of the samples in the organic petrology method, the microscope features of the sedimentary organic matter were studied. The results indicate that three types of kerogens present in the measured samples. Kerogen type I consists of the laminate algainite, abundant sporinite and only little content of cutinite, which can mainly generate oil. The generation hydrocarbon components of the type II kerogen are dominated by the sporinite, cutinite and little the exinite debris. The type III kerogen is comprised of the sporinite and debris of the exinite with some components of gas generation. Through the analysis of the experiments, the organic kerogen of the Lucaogou formation is mostly comprised of the type I, partially type II, and particularly type III. In Hongyanchi formation, the organic type is mixed by the types II and III. The plot of the （$1＋$2） or TOC value and the content of exinite show two trends. From the evolution of burial and the Permian source rocks in Changji Depression, the Permian formation source rock has ended the generation of hydrocarbon. A significant difference in constituents of the organic macerals among three kerogens in these samples leads to the distinction of the potential hydrocarbon generation. The Lucaogou formation for kerogen type I has better potential hydrocarbon generation. It can reach the oil peak with Ro ratio Of 0.9%. For the kerogen II, the oil peak of the source rocks comes late with the Ro ratio of 1.0% with less quantity of the generation hydrocarbon than the kerogen I. For type III, it can mainly generate gas and reach the gas peak with the Ro ratio of 1.3%. In a word, the Lucaogou formation and Hongyanchi formation source rocks with high organic richness in Permian source rocks have well exploration prospects.展开更多
Dear Editor,In recent years,the incidence of human infections caused by emerging or re-emerging pathogens has rapidly increased.Diseases that were once regional now have the ability to spread globally in a short amoun...Dear Editor,In recent years,the incidence of human infections caused by emerging or re-emerging pathogens has rapidly increased.Diseases that were once regional now have the ability to spread globally in a short amount of time and pose a wider threat to public health(Weaver et al.2018).Yellow fever virus(YFV,family Flaviviridae,genus Flavivirus)is a mosquito-borne flavivirus that causes yellow fever in humans and has been endemic in Africa and Latin America for many years(Domingo et al.2018).展开更多
In the paper, we have discovered the abnormal area distribution features of maximum variation values of ground motion parameter uncertainty with different probabilities of exceedance in 50 years within the range of 10...In the paper, we have discovered the abnormal area distribution features of maximum variation values of ground motion parameter uncertainty with different probabilities of exceedance in 50 years within the range of 100°-120°E, 29°-42°N for the purpose to solve the problem that abnormal areas of maximum variation values of ground motion parameter uncertainties emerge in a certain cities and towns caused by seismicity parameter uncertainty in a seismic statistical region in an inhomogeneous distribution model that considers tempo-spatial nonuniformity of seismic activity. And we have also approached the interrelation between the risk estimation uncertainty of a site caused by seismicity parameter uncertainty in a seismic statistical region and the delimitation of potential sources, as well as the reasons for forming abnormal areas. The results from the research indicate that the seismicity parameter uncertainty has unequal influence on the uncertainty of risk estimation at each site in a statistical region in the inhomogeneous distribution model, which relates to the scheme for delimiting potential sources. Abnormal areas of maximum variation values of ground motion parameter uncertainty often emerge in the potential sources of Mu greater than or equal 8 (Mu is upper limit of a potential source) and their vicinity. However, this kind of influence is equal in the homogeneous distribution model. The uncertainty of risk estimation of each site depends on its seat. Generally speaking, the sites located in the middle part of a statistical region are only related to the seismicity parameter uncertainty of the region, while the sites situated in or near the juncture of two or three statistical regions might be subject to the synthetic influences of seismicity parameter uncertainties of several statistical regions.展开更多
Electric potential near a wall for plasma with the surface produced negative ions with magnetic field increasing toward a wall is investigated analytically. The potential profile is derived analytically by using a pla...Electric potential near a wall for plasma with the surface produced negative ions with magnetic field increasing toward a wall is investigated analytically. The potential profile is derived analytically by using a plasma-sheath equation, where negative ions produced on the plasma grid （PG） surface are considered in addition to positive ions and electrons. The potential profile depends on the amount and the temperature of the surface produced negative ions and the profile of the magnetic field. The negative potential peak is formed in the sheath region near the PG surface for the case of strong surface production of negative ions or low temperature negative ions. As the increase rate of the magnetic field near the wall becomes large, the negative potential peak becomes small.展开更多
基金supported by the National Natural Science Foundation of China(No.41975156)and the Fundamental Research Funds for the Central Universities.
文摘Oxidative potential(OP)can be used as an indicator of the health risks of particulate matter in the air.To study the variation and sources of OP,we conducted an observation of PM_(2.5) in a megacity in southern China in winter and spring of 2021.The results show that the average concentration of PM_(2.5) decreased by 47%from winter to spring,while volume-normalized and mass-normalized OP(i.e.,OP_(v) and OP_(m))increased by 6%and 69%,respectively.It suggests that the decline of PM_(2.5) may not necessarily decrease the health risks and the intrinsic toxicity of PM_(2.5).Variations of OP_(v) and OP_(m) among different periods were related to the different source contributions and environmental conditions.The positive matrix factorization model was used to identify the major sources of OP_(v).OP_(v) was mainly contributed by biomass burning/industrial emissions(29%),soil/road dust(20%),secondary sulfate(14%),and coal combustion(13%)in winter.Different major sources were resolved to be secondary sulfate(36%),biological sources(21%),and marine vessels(20%)in spring,presenting the substantial contribution of biological sources.The analysis shows strong associations between OP_(v) and both live and dead bacteria,further confirming the important contribution of bioaerosols to the enhancement of OP.This study highlights the importance of understanding OP in ambient PM_(2.5) in terms of public health impact and provides a new insight into the biological contribution to OP.
基金supported by the CNPC Science and Technology Major Project of the Fourteenth Five-Year Plan(2021DJ0101)the National Natural Science Foundation of China(U19B600302,41872148)。
文摘The Early Cambrian Yuertusi Formation(Є_(1)y)in the Tarim Basin of China deposits a continuously developed suite of organic-rich black mudstones,which constitute an important source of oil and gas reservoirs in the Paleozoic.However,its hydrocarbon generation and evolution characteristics and resource potential have long been constrained by deeply buried strata and previous research.In this paper,based on the newly obtained ultra-deep well drilling data,the hydrocarbon generation and expulsion model ofЄ_(1)y shale was established by using data-driven Monte Carlo simulation,upon which the hydrocarbon generation,expulsion,and retention amounts were calculated by using the diagenetic method.The research indicates that theЄ_(1)y shale reaches the hydrocarbon generation and expulsion threshold at equivalent vitrinite reflectances of 0.46%and 0.72%,respectively.The cumulative hydrocarbon generation is 68.88×10^(10)t,the cumulative hydrocarbon expulsion is 35.59×10^(10)t,and the cumulative residual hydrocarbon is 33.29×10^(10)t.This paper systematically and quantitatively calculates the hydrocarbon expulsion at various key geological periods for theЄ_(1)y source rocks in the study area for the first time,more precisely confirming that the black shale of theЄ_(1)y is the most significant source rock contributing to the marine oil and gas resources in the Tarim Basin,filling the gap in hydrocarbon expulsion calculation in the study area,and providing an important basis for the formation and distribution of Paleozoic hydrocarbon reservoirs.The prospect of deep ultra-deep oil and gas exploration in the Tarim Basin is promising.Especially,the large area of dolomite reservoirs under the Cambrian salt and source rock interiors are the key breakthrough targets for the next exploration in the Tarim Basin.
基金supported by the Science and Technology Program of Fujian Province,China(No.2023R1014002)the National Natural Science Foundation of China(No.41471390).
文摘The toxicity of PM_(2.5)does not necessarily change synchronously with its mass concentration.In this study,the chemical composition(carbonaceous species,water-soluble ions,and metals)and oxidative potential(dithiothreitol assay,DTT)of PM_(2.5)were investigated in 2017/2018 and 2022 in Xiamen,China.The decrease rate of volume-normalized DTT(DTTv)(38%)was lower than that of PM_(2.5)(55%)between the two sampling periods.However,the mass-normalized DTT(DTTm)increased by 44%.Clear seasonal patterns with higher levels in winter were found for PM_(2.5),most chemical constituents and DTTv but not for DTTm.The large decrease in DTT activity(84%−92%)after the addition of EDTA suggested that watersoluble metals were the main contributors to DTT in Xiamen.The increased gap between the reconstructed and measured DTTv and the stronger correlations between the reconstructed/measured DTT ratio and carbonaceous species in 2022were observed.The decrease rates of the hazard index(32.5%)and lifetime cancer risk(9.1%)differed from those of PM_(2.5)and DTTv due to their different main contributors.The PMF-MLR model showed that the contributions(nmol/(min·m^(3)))of vehicle emission,coal+biomass burning,ship emission and secondary aerosol to DTTv in 2022 decreased by 63.0%,65.2%,66.5%,and 22.2%,respectively,compared to those in 2017/2018,which was consistent with the emission reduction of vehicle exhaust and coal consumption,the adoption of low-sulfur fuel oil used on board ships and the reduced production of WSOC.However,the contributions of dust+sea salt and industrial emission increased.
基金supported by the National Natural Science Foundation of China(Nos.42121004,42275107,and 42077205)the National Key Research and Development Plan(No.2023YFC3706202)+1 种基金the Foundational and Applied Basic Research in Guangzhou in 2023(No.2023A04J0251)the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province(No.2019B121205004)。
文摘This study tracked the characteristics of atmospheric wet deposition of the toxic element arsenic(As)at both urban(Guangzhou(GZ))and forested(Dinghushan Natural Reserve(DHS))sites within the Pearl River Delta(PRD)region between 2016 and 2019,examining its correlation with rainfall patterns.Additionally,by employing backward trajectory analysis and the potential source contribution function(PSCF)in conjunction with pertinent emission inventories,we pinpointed the main pathways of atmospheric arsenic transport and evaluated the emission contributions from priority source areas.The study revealed that the atmospheric arsenic wet deposition fluxes at the GZ and DHS sites exhibited a trend of increase followed by a decrease over the four-year period.Wet season deposition fluxes were more than triple those of the dry season,with urban site showing a difference of over four times.Notably,wet season As deposition at both sites was predominantly affected by heavy rainfall from marine air masses,constituting 31%of the total deposition.The predominant trajectory directions contributing to arsenic deposition at GZ and DHS were northeast(55%)and south(53%),respectively.The primary source areas for both sites were largely outside the PRD region,with the GZ site having 80%to 95%of its source area in the non-PRD region,compared to 69%to 88%at the DHS site.Furthermore,non-PRD areas contributed approximately 65%to arsenic emissions for both sites,with the industrial sector being the dominant emission source,exceeding 97%of the total emissions.
基金supported by the National Natural Science Foundation of China (No.42201151)the Basic Research Fund of the Chinese Academy of Meteorological Sciences (Nos.2023Z004 and 2024Z007)。
文摘Black carbon (BC) aerosols are considered key factors that contribute to rapid climate warming and ice melt in the Arctic region.However,compared with long-term observations from land-based stations,observational data over the Arctic Ocean remain relatively scarce.Four Arctic scientific expeditions were conducted in the summer and early autumn of 2010,2012,2016,and 2018 via the Chinese research vessel Xue Long,during which the BC concentrations along the routes were measured via light absorption methods.In this work,the spatiotemporal distribution characteristics of BC over the Arctic Ocean were examined on the basis of these observations.The potential sources of BC along the various routes were analyzed via the weighted potential source contribution function and weighted concentrationweighted trajectory methods of the hybrid single-particle Lagrangian integrated trajectory model in conjunction with Arctic transport potential climate model simulations.The analysis results indicated that wildfires in the western Aleutian Islands,Siberia,and Far East regions were the primary contributors to the BC aerosol concentration observed along the Arctic expedition routes in summer,identifying these regions as major potential source areas.
基金supported by the National Natural Science Foundation of China(No.42305109)Quzhou Municipal Science and Technology Bureau(No.2023K222).
文摘Inhalation of atmospheric PM_(2.5)can induce the generation of excessive reactive oxygen species(ROS)in human alveoli,triggering local and systemic inflammation,which can directly or indirectly result in respiratory and cardiovascular diseases.In this study,we assessed the oxidative potential(OP)of fresh and O_(3)-aged PM_(2.5)particles from various urban and rural emission sources using the dithiothreitol(DTT)method.Our results revealed variations in the OP of fresh PM_(2.5)among different emission sources,with biomass burning sources exhibiting the highest OP,followed by industrial areas,vehicular emissions,cooking emissions,and suburban areas,respectively.Water-soluble organics and transition metals might potentially exert significant influence on particle OP.O_(3)aging notably decreased the OP of PM_(2.5)particles,possibly due to the oxidation of highly DTT-active components into low redox-active small molecules.Moreover,the evolution of OP in different PM_(2.5)components,including methanol-soluble and insoluble fractions,exhibited distinct responses to O_(3)aging for source-oriented PM_(2.5).Additionally,differences in chemical composition between fresh and aged PM_(2.5)were further elucidated through measurements of component-dependent hygroscopic behaviors and phase transitions.This study systematically delineates variances in the toxic potential of fresh and O_(3)-aged PM_(2.5)from various anthropogenic sources.The findings highlight the intrinsic compositional dependence of particle OP and provide essential insights for assessing the health effects of source-oriented PM_(2.5),as well as for formulating human health protection policies.
基金supported by the National Natural Science Foundation of China(Nos.41905108 and 42130704).
文摘Carbonyl compounds play a pivotal role in the formation of secondary pollutants such as O_(3) and SOA,signifi-cantly impacting air quality and human health.This study extended the observation period compared to previous research,providing a long-term perspective on carbonyl compound variations and their environmental implica-tions.Atmospheric observations were conducted at Beijing(BJ)and Xianghe(XH)during the summer and winter months of 2018,2019,and 2023 to study the sources and impacts of carbonyl compounds in typical urban areas and peri‑urban areas.Notably,concentrations in the summer of 2023 increased compared to 2018 and 2019.The predominant carbonyl compounds—formaldehyde,acetaldehyde,and acetone—accounted for over 60%of the total.The mean values of OFP in BJ ranged from 18.55 to 58.61μg/m3,lower than those in XH(29.82 to 65.48μg/m3),with formaldehyde and acetaldehyde contributing over 80%of the total.SOAP exhibited a similar pattern,with values in XH(69.21 to 508.55μg/m3)significantly exceeding those in BJ(34.47 to 159.78μg/m3).The PMF model highlighted vehicle exhaust,secondary pollution,and biomass combustion as major sources of carbonyl compounds,emphasizing differences in source contributions between the two regions.This study’s com-parative analysis over different years and locations provides new insights into the dynamic changes in carbonyl compounds and their environmental importance.These results not only reinforce the importance of carbonyl compounds regulation but also offer a valuable reference for evaluating and refining emission control strategies during this period.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0208)the National Natural Science Foundation of China(Nos.42171148 and 42330512)the Key R&D Project from the Science and Technology Department of Tibet(No.XZ202501ZY0030).
文摘Nitrogen(N)and phosphorus(P)are essential nutrients and can significantly impact primary productivity of the ecosystem causing water environmental problems.However,their cycling mechanisms are not well understood in alpine mountains with climate change.Hence,94 samples of river water were collected from 2018 to 2020 in the headwaters of the Shule River Basin to assess the nutrients spatiotemporal distribution and combined ap-proach of water quality index to assess water quality and potential sources.The findings depict that high nutrient concentrations were found to coincide with snowmelt and glacial meltwater and rainfall recharge periods,while total flux peaked from June to September due to increased runoff.Notably,total nitrogen(TN)concentrations were significantly higher near the town,primarily attributed to the replenishment of nitrate(NO_(3)^(‒)-N)from live-stock manure.The high total P(TP)was near the glacier,which was attributed to the transportation of glacial sediments into the river,and pH was another critical factor.N was the primary nutrient limiting factor for the growth of phytoplankton in river water.Although the migration and transport of nutrients have altered with climate change,river water quality is good in alpine mountains based on an overall evaluation.These findings contribute to enriching nutrient datasets and highlight the importance of water resource management and water quality assessment in sensitive and fragile alpine mountains.
基金supported by the China Postdoctoral Science Foundation
文摘Carboniferous source rocks identified by drilling in Santanghu （三塘湖） Basin were evaluated for their source potential, employing organic geochemistry and RockEval pyrolysis. The organic matter origin and depositional environment of these samples were also determined through biomarker analysis. Most of the Carboniferous source rocks in Santanghu Basin are characterised by high values of total organic carbon （TOC） content and high extractable organic matter content and hydrocarbon yields, indicating that they are organicrich source rocks with high oil generative potential. The organic matter is predominantly Type I and Type II kerogen with a minor contribution of Type III kerogen, as demonstrated by its pyrolysis parameters and carbon isotope values. According to Ro （%） and T max values, most of the studied samples are at earlyto middle-thermal mature stage; only a few of the samples are at a highly mature stage （past peak oil generation）. The biomarker analysis reveals a dominance of algal/bacterial organic matter input, with a minor contribution of land plant material. Pr/Ph ratio supports a suboxic depositional condition, consistent with a neritic or marine-continental alternating environment proposed by predecessor.
基金supported by The National Key Research and Development Program of China(No.2017YFC0209500)the National Natural Science Foundation of China(Nos.91744204,41822703,and 91844301)National research program for key issues in air pollution control(No.DQGG-0103)。
文摘A distinctive kind of organic carbon aerosol that could absorb ultraviolet-visible radiation is called brown carbon(Br C),which has an important positive influence on radiative budget and climate change.In this work,we reported the absorption properties and potential source of Br C based on a seven-wavelength aethalometer in the winter of 2018–2019 at an urban site of Sanmenxia in Fenwei Plain in central China.Specifically,the mean value of Br C absorption coefficient was 59.6±36.0 Mm^(-1) at 370 nm and contributed 37.7%to total absorption,which made a significant impact on visibility and regional environment.Absorption coefficients of Br C showed double-peak pattern,and Br C had shown small fluctuations under haze days compared with clean days.As for the sources of Br C,Br C absorption coefficients expressed strong correlations with element carbon aerosols and primary organic carbon aerosols,indicating that most of Br C originated from primary emissions.The linear correlations between trace metal elements(K,As,Fe,Mn,Zn,and Pb)and Br C absorption coefficients further referred that the major sources of Br C were primary emissions,like coal burning,biomass burning,and vehicle emissions.The moderate relationship between Br C absorption coefficients and secondary organic aerosols suggested that secondary production of Br C also played an important role.The 120 hr backward air mass trajectories analysis and concentration-weighted trajectories analysis were also used to investigate potential sources of Br C in and around this area,which inferred most parts of Br C were derived from local emissions.
基金supported by the National Natural Science Foundation of China(No.91543110)the fellowship granted by China Scholarship Council。
文摘The chemical characteristics,oxidative potential,and sources of PM_(2.5)were analyzed at the urban sites of Lahore and Peshawar,Pakistan in February 2019.Carbonaceous species,water soluble ions,and metal elements were measured to investigate the chemical composition and sources of PM_(2.5).The dithiothreitol(DTT)consumption rate was measured to evaluate the oxidative potential of PM_(2.5).Both cities showed a high exposure risk of PM_(2.5)regarding its oxidative potential(DTT v).Carbonaceous and some of the elemental species of PM_(2.5)correlated well with DTT v in both Lahore and Peshawar.Besides,the DTT v of PM_(2.5)in Lahore showed significant positive correlation with most of the measured water soluble ions,however,ions were DTT-inactive in Peshawar.Due to the higher proportions of carbonaceous species and metal elements,Peshawar showed higher mass-normalized DTT activity of PM_(2.5)compared to Lahore although the average PM_(2.5)concentration in Peshawar was lower.The high concentrations of toxic metals also posed serious non-carcinogenic and carcinogenic risks to the residents of both cities.Principle component analysis coupled with multiple linear regression was applied to investigate different source contributions to PM_(2.5)and its oxidative potential.Mixed sources of traffic and road dust resuspension and coal combustion,direct vehicle emission,and biomass burning and formation of secondary aerosol were identified as the major sources of PM_(2.5)in both cities.The findings of this study provide important data for evaluation of the potential health risks of PM_(2.5)and for formulation of efficient control strategies in major cities of Pakistan.
文摘Magnitude and distance of major potential source are needed in order to determine duration time of artificial ground motion and to determine the type of response spectrum (near field or far field) when using the seismic intensity zonation map. The magnitude probabilistic distribution function of seismic belt and the magnitude and space joint distribution function for given intensity of the site in a potential Source are provided. Then the basicformula of calculating expected magnitude and expected distance are developed. Several examples for calculating expected magnitude and expected distance in northern China are discussed. These results show that expected magnitude and expected distance are related not only to geometry of potential source and magnitude but also to the intensity of the site with certain exceeding probability.
基金supported by National Key Research and Development Plan(No.2017YFC0210100)the National Natural Science Foundation of China(Nos.41905086,41905107,42077205,41425020)+4 种基金the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province(No.2019B121205004)the Natural Science Foundation of Guangdong Province(No.2019A1515011291)the China Postdoctoral Science Foundation(No.2020M683174)the Air Quip(High resolution Air Quality Information for Policy)Project funded by the Research Council of Norway,the Collaborative Innovation Center of Climate Change,Jiangsu province,China,the high-performance computing platform of Jinan University,the Mt.Dinghu Forest Ecosystem Research Station,Chinese Academy of Sciences(CAS)the Comprehensive Observation and Study Site of Urban Meteorology and Environment,Sun Yat-sen University,and the Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies(No.2020B1212060025)
文摘This study attempts to identify the dominant transport pathways,potential source areas,and their seasonal variation at sites with high inorganic nitrogen(IN)wet deposition flux in southern China.This is a long-term study(2010-2017)based on continuous deposition measurements at the Guangzhou urban site(GZ)and the Dinghushan Natural Reserve site(DHS)located in the Pearl River Delta(PRD)region.A dataset on monthly IN concentration in precipitation and wet deposition flux were provided.The average annual fluxes measured at both sites(GZ:33.04±9.52,DHS:20.52±10.22 kg N/(ha·year))were higher,while the ratios of reduced to oxidized N(GZ:1.19±0.77,DHS:1.25±0.84)were lower compared with the national mean level and the previous reported level throughout the PRD region.The dominant pathways were not always consistent with the highest proportional trajectory clusters.The transport pathways contributing most of deposition were identified in the north and northnortheast in the dry season and in the east-southeast,east,and south-southwest in the wet season.A weighted potential source contribution function(WPSCF)value>0.3 was determined reasonably to define the potential source area.Emission within the PRD region contributed the majority(≥95%at both sites)of the IN deposition in the wet season,while the contribution outside the region increased significantly in the dry season(GZ:27.86%,DHS:95.26%).Our results could help create more effective policy to control precursor emissions for IN fluxes,enabling reduction of the ecological risks due to excessive nitrogen.
基金This research is supported by the Joint Fund of the National Natural Science Foundation of China(grant number U19B6003-02)the Cooperation Program of PetroChina Liaohe Oilfield Company(grant Number HX20180604)the AAPG Foundation Grants-in-Aid Program(grant number 22269437).This study has benefited considerably from PetroChina Liaohe Oilfield Company for data support.We also thank the editor and the anonymous reviewers for their professional suggestions and comments.
文摘Kerogen types exert a decisive effect on the onset and capacity of hydrocarbon generation of source rocks.Lacustrine source rocks in the Liaohe Western Depression are characterized by thick deposition,high total organic carbon(TOC)content,various kerogen types,and a wide range of thermal maturity.Consequently,their hydrocarbon generation potential and resource estimation can be misinterpreted.In this study,geochemical tests,numerical analysis,hydrocarbon generation kinetics,and basin modeling were integrated to investigate the differential effects of kerogen types on the hydrocarbon generation potential of lacustrine source rocks.Optimized hydrocarbon generation and expulsion(HGE)models of different kerogen types were established quantitatively upon abundant Rock-Eval/TOC/vitrinite reflectance(R_(o))datasets.Three sets of good-excellent source rocks deposited in the fourth(Es4),third(Es3),and first(Es1)members of Paleogene Shahejie Formation,are predominantly types I-II_(1),II_(1)-II_(2),and II-III,respectively.The activation energy of types I-II_(2)kerogen is concentrated(180-230 kcal/mol),whereas that of type III kerogen is widely distributed(150-280 kcal/mol).The original hydrocarbon generation potentials of types I,II_(1),II_(2),and III kerogens are 790,510,270,and 85 mg/g TOC,respectively.The Ro values of the hydrocarbon generation threshold for type I-III source rocks gradually increase from 0.42%to 0.74%,and Ro values of the hydrocarbon expulsion threshold increase from 0.49%to 0.87%.Types I and II_(1)source rocks are characterized by earlier hydrocarbon generation,more rapid hydrocarbon expulsion,and narrower hydrocarbon generation windows than types II_(2)and III source rocks.The kerogen types also affect the HGE history and resource potential.Three types(conventional,tight,and shale oil/gas)and three levels(realistic,expected,and prospective)of hydrocarbon resources of different members in the Liaohe Western Depression are evaluated.Findings suggest that the Es3 member has considerable conventional and unconventional hydrocarbon resources.This study can quantitatively characterize the hydrocarbon generation potential of source rocks with different kerogen types,and facilitate a quick and accurate assessment of hydrocarbon resources,providing strategies for future oil and gas exploration.
文摘The lower Tertiary Eh3 is divided into two sections： the upper members of Eh3 and the lower members of Eh3 in the Biyang Depression. The first section is generally regarded as a key target of oil and gas exploration, but the resource potential of the lower members of Eh3 has been neglected. We have obtained new knowledge about Eh3 from comprehensive geological research. The lower members of Eh3 are high-quality and main source rocks, which have good oil and gas resource potential. This is a new direction for oil and gas exploration. The geochemistry characteristics of source rocks of the lower members of Eh3 in the lower Tertiary of the Biyang Depression were analyzed in detail. A basin modeling method was applied to hydrocarbon generation of the lower and upper members of Eh3 source rocks, the oil and gas resource potential was comparatively analyzed, and then favorable tectonic zones were pointed out. In the lower members of Eh3, a set of semi-deep lake to deep lake high-quality source rocks occurs rich in algae organisms, mainly of type II1, with a high abundance of organic matter. Most of the source rocks are just in the peak stage of hydrocarbon generation, which is a favorable foundation for forming abundant oil and gas resources in the Biyang Depression. The comparative analysis of the hydrocarbon- generation quantities between lower and upper members of the Eh3 source rocks shows that the lower members of Eh3 have good oil and gas resource potential, and the hydrocarbon-generation quantity accounts for 51% of the total in Eh3. Specifically, the oil-generating quantity accounts for 50% of the total and the gas-generating quantity accounts for two thirds of the total. Therefore, source rocks in the lower members of Eh3 of the Biyang Depression have good oil and gas resource potential, which is a key factor for future deep oil and gas exploration.
基金supported by the Major Program of Science and Technology of Hainan Province,China(No.ZDKJ202007)the Special Foundation of Government Financial of Hainan Province,China(No.ZC2018-196)the Youth Innovation Foundation of Hainan Research Academy of Environmental Sciences,China(No.QNCX2021002)。
文摘Based on one-year observation,the concentration,sources,and potential source areas of volatile organic compounds(VOCs)were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou,China.The results showed that the annual average concentration of total VOCs(TVOCs)was 11.4 ppb V,and the composition was dominated by alkanes(8.2 ppb V,71.4%)and alkenes(1.3 ppb V,20.5%).The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening.The greatest contribution to ozone formation potential(OFP)was made by alkenes(51.6%),followed by alkanes(27.2%).The concentrations of VOCs and nitrogen dioxide(NO_(2))in spring and summer were low,and it was difficult to generate high ozone(O_(3))concentrations through photochemical reactions.The significant increase in O_(3)concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast.Traffic sources(40.1%),industrial sources(19.4%),combustion sources(18.6%),solvent usage sources(15.5%)and plant sources(6.4%)were identified as major sources of VOCs through the positive matrix factorization(PMF)model.The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function(PSCF)and concentration-weighted trajectory(CWT)models.Overall,the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport,and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou,thereby reducing the generation of O_(3).
基金Project(2011ZX05002-006)supported by the National Science and Technology Project,China
文摘From the outcrops in the Yaomoshan and Hongyanchi sections, oil shales, deep dark mudstones or black mudstones with better organic richness were found. Through the analysis of the samples in the organic petrology method, the microscope features of the sedimentary organic matter were studied. The results indicate that three types of kerogens present in the measured samples. Kerogen type I consists of the laminate algainite, abundant sporinite and only little content of cutinite, which can mainly generate oil. The generation hydrocarbon components of the type II kerogen are dominated by the sporinite, cutinite and little the exinite debris. The type III kerogen is comprised of the sporinite and debris of the exinite with some components of gas generation. Through the analysis of the experiments, the organic kerogen of the Lucaogou formation is mostly comprised of the type I, partially type II, and particularly type III. In Hongyanchi formation, the organic type is mixed by the types II and III. The plot of the （$1＋$2） or TOC value and the content of exinite show two trends. From the evolution of burial and the Permian source rocks in Changji Depression, the Permian formation source rock has ended the generation of hydrocarbon. A significant difference in constituents of the organic macerals among three kerogens in these samples leads to the distinction of the potential hydrocarbon generation. The Lucaogou formation for kerogen type I has better potential hydrocarbon generation. It can reach the oil peak with Ro ratio Of 0.9%. For the kerogen II, the oil peak of the source rocks comes late with the Ro ratio of 1.0% with less quantity of the generation hydrocarbon than the kerogen I. For type III, it can mainly generate gas and reach the gas peak with the Ro ratio of 1.3%. In a word, the Lucaogou formation and Hongyanchi formation source rocks with high organic richness in Permian source rocks have well exploration prospects.
基金supported by grants from the National Science and Technology Major Project of China (2016ZX10004222 and 2016YFC1200800)Strategic Priority Research Program of the Chinese Academy of Sciences (XDB29010102)+5 种基金Sanming Project of Medicine in Shenzhen (SZSM201412003)Shenzhen Municipal Government of China (JCYJ20160427151920801)Beijing Municipal Science & Technology Commission (Z161100000116049)the National Natural Science Foundation of China (NSFC) International Cooperation and Exchange Program (816110193)supported by the NSFC Outstanding Young Scholars (31822055)Youth Innovation Promotion Association of Chinese Academy of Sciences (CAS) (2017122)
文摘Dear Editor,In recent years,the incidence of human infections caused by emerging or re-emerging pathogens has rapidly increased.Diseases that were once regional now have the ability to spread globally in a short amount of time and pose a wider threat to public health(Weaver et al.2018).Yellow fever virus(YFV,family Flaviviridae,genus Flavivirus)is a mosquito-borne flavivirus that causes yellow fever in humans and has been endemic in Africa and Latin America for many years(Domingo et al.2018).
基金Joint Seismological Science Foundation of China (103051).
文摘In the paper, we have discovered the abnormal area distribution features of maximum variation values of ground motion parameter uncertainty with different probabilities of exceedance in 50 years within the range of 100°-120°E, 29°-42°N for the purpose to solve the problem that abnormal areas of maximum variation values of ground motion parameter uncertainties emerge in a certain cities and towns caused by seismicity parameter uncertainty in a seismic statistical region in an inhomogeneous distribution model that considers tempo-spatial nonuniformity of seismic activity. And we have also approached the interrelation between the risk estimation uncertainty of a site caused by seismicity parameter uncertainty in a seismic statistical region and the delimitation of potential sources, as well as the reasons for forming abnormal areas. The results from the research indicate that the seismicity parameter uncertainty has unequal influence on the uncertainty of risk estimation at each site in a statistical region in the inhomogeneous distribution model, which relates to the scheme for delimiting potential sources. Abnormal areas of maximum variation values of ground motion parameter uncertainty often emerge in the potential sources of Mu greater than or equal 8 (Mu is upper limit of a potential source) and their vicinity. However, this kind of influence is equal in the homogeneous distribution model. The uncertainty of risk estimation of each site depends on its seat. Generally speaking, the sites located in the middle part of a statistical region are only related to the seismicity parameter uncertainty of the region, while the sites situated in or near the juncture of two or three statistical regions might be subject to the synthetic influences of seismicity parameter uncertainties of several statistical regions.
文摘Electric potential near a wall for plasma with the surface produced negative ions with magnetic field increasing toward a wall is investigated analytically. The potential profile is derived analytically by using a plasma-sheath equation, where negative ions produced on the plasma grid （PG） surface are considered in addition to positive ions and electrons. The potential profile depends on the amount and the temperature of the surface produced negative ions and the profile of the magnetic field. The negative potential peak is formed in the sheath region near the PG surface for the case of strong surface production of negative ions or low temperature negative ions. As the increase rate of the magnetic field near the wall becomes large, the negative potential peak becomes small.
