A methodology for identifying volatile organic compounds （VOCs） and determining air quality of indoor air has been developed. The air samples are collected using pump samplers by the inhabitants when they perceive o...A methodology for identifying volatile organic compounds （VOCs） and determining air quality of indoor air has been developed. The air samples are collected using pump samplers by the inhabitants when they perceive odorous and/or discomfort episodes. Glass multi-sorbent tubes are connected to the pump samplers for the retention of VOC. The analysis is performed by automatic thermal desorption （ATD） coupled with gas chromatography-mass spectrometry （GC/MS）. This methodology can be applied in cases of sick building syndrome （SBS） evaluation, in which building occupants experience a series of varied symptoms that appear to be linked to time spent in the building. Chemical pollutants concentrations （e.g., VOC） have been described to contribute to SBS. To exemplify the methodology, a qualitative determination and an evaluation of existing VOC were performed in a dwelling where the occupants experienced the SBS symptoms. Higher total VOC （TVOC） levels were detected during episodes in indoor air （1.33 ±1.53 mg/m^3） compared to outdoor air （0.71± 0.46 mg/m^3）. The concentrations of individual VOCs, such as ethanol, acetone, isopropanol, 1-butanol, acetic acid, acetonitrile and 1-methoxy-2-propanol, were also higher than the expected for a standard dwelling. The external source of VOC was found to be an undeclared activity of storage and manipulation of solvents located at the bottom of a contiguous building.展开更多
Groundwater residence time is a fundamental property of groundwater to understand important hydrogeological issues,such as deriving sustainable abstraction volumes,or,the evolution of groundwater quality.The anthropog...Groundwater residence time is a fundamental property of groundwater to understand important hydrogeological issues,such as deriving sustainable abstraction volumes,or,the evolution of groundwater quality.The anthropogenic trace gases chlorofluorocarbons (CFC-11,CFC-12 and CFC-113) and sulphur hexafluoride (SF6) are ideal in this regard because they have been released globally at known rates and become dissolved in groundwater following Henry’s Law,integrating over large spatial (global) and temporal (decades) scales.The CFCs and SF6 are able to date groundwater up to w100 years old with the caveat of certain simplifying assumptions.However,the inversion of environmental tracer concentrations (CFCs and SF6) to derive groundwater age rests on the accurate determination of groundwater recharge parameters,namely temperature,elevation,salinity and excess air,in addition to resolving the potential for contamination,degradation and unsaturated zone effects.This review explores the fundamentals of CFC-11,CFC-12,CFC-113 and SF6 as environmental tracers of groundwater age and recommends complementary techniques throughout.Once this relatively simple and inexpensive technique has been used to determine initial concentrations at the recharge zone,setting the groundwater dating ‘clock’ to zero,this review then explores the meaning of groundwater ‘age’ in relation to measured environmental tracer concentrations.It is shown that the CFCs and SF6 may be applied to a wide-range of hydrogeological problems and suggests that environmental tracers are particularly powerful tools when integrated with numerical flow and transport models.展开更多
This work investigated the influence of Sn and Mo on corrosion behavior of ferrite-pearlite steel in the simulated bottom plate environment of cargo oil tank. The results indicate that the corrosion rate of three ferr...This work investigated the influence of Sn and Mo on corrosion behavior of ferrite-pearlite steel in the simulated bottom plate environment of cargo oil tank. The results indicate that the corrosion rate of three ferrite-pearlite steels increased with extending the immersion time due to the continuous accumulation of the residual Fe3C. However, the addition of Sn or the combined addition of Sn and Mo could reduce the corrosion rate of Sn containing steel and Sn-Mo containing steel to 37.5% and 20% of that of carbon steel, respectively. Moreover, the cathodic reaction of Sn containing steel and Sn-Mo containing steel was always controlled by the charge transfer step during the whole immersion test, while that of carbon steel was gradually transformed into the diffusion-controlled process. These results were mainly related with the deposition of metallic Sn and Mo on the steel surface. The metallic Sn and Mo with uniform distribution restrained the galvanic effect through suppressing both the anodic dissolution of ferrite and cathodic hydrogen evolution reaction on the residual Fe3C.展开更多
The effects of bentonite content on the corrosion behavior of low carbon steel in 5 mM NaHCO3+ 1 mM NaCl + 1 mM Na2SO4 solution were investigated by electrochemical measurements combined with X-ray diffraction(XRD) an...The effects of bentonite content on the corrosion behavior of low carbon steel in 5 mM NaHCO3+ 1 mM NaCl + 1 mM Na2SO4 solution were investigated by electrochemical measurements combined with X-ray diffraction(XRD) and scanning electron microscopy(SEM). In the initial immersion stage, the cathodic process of low carbon steel corrosion was dominated by the reduction of dissolved oxygen, while it transformed to the reduction of ferric corrosion products with the immersion time. The presence of bentonite colloids could suppress the cathodic reduction of oxygen due to their barrier effect on the diffusion of oxygen. However, the barrier performance of bentonite layer was gradually deteriorated due to the coagulation and separation of bentonite colloids caused by the charge neutralization of iron corrosion products dissolved from the steel substrate. More bentonite colloids could maintain the barrier effect for a long time before it was deteriorated by the accumulation of corrosion products. Conversely,it could lose the performance completely, and the corrosion behavior of low carbon steel reverted to the same as that in the blank solution.展开更多
China is the largest producer and consumer of hydrochlorofluorocarbons （HCFCs）, and the production of HCFC-22 accounts for more than 80% of all HCFCs. This paper concentrates on the residential air-conditioner indus...China is the largest producer and consumer of hydrochlorofluorocarbons （HCFCs）, and the production of HCFC-22 accounts for more than 80% of all HCFCs. This paper concentrates on the residential air-conditioner industry and analyzes the environmental benefits of accelerating the phase-out of HCFC-22 in China. According to the comparison of the baseline and phase-out scenarios of HCFC-22, the findings show that using HC-290 （propane） as a refrigerant alternative will directly reduce the greenhouse effect, and indirectly reduce the emission of greenhouse gases due to a reduction in the electricity consumption. The comparison of two scenarios of HC-290 and HFC-410A refrigerant alternatives shows that the use of HC-290 refrigerant will produce significantly higher environmental benefits than the HFC-410A refrigerant.展开更多
Globally,sub-optimal use of nitrogen (N) fertiliser and elevated N irrigation groundwater have led to high leached nitrate (NO_(3)^(–)) losses from protected vegetable field systems.Optimising fertiliser and irrigati...Globally,sub-optimal use of nitrogen (N) fertiliser and elevated N irrigation groundwater have led to high leached nitrate (NO_(3)^(–)) losses from protected vegetable field systems.Optimising fertiliser and irrigation management in different soil types is crucial to reduce future N loads from such systems.The present 4-year study examined leached N loads from lysimeter monitoring arrays set up across 18 protected vegetable system sites encompassing the dominant soil types of northern China.The treatments applied at each field site were:1) a high N and high irrigation input treatment (HNHI);2) a low N but high irrigation input treatment (LNHI) and 3) a low N with low irrigation input treatment (LNLI).Results showed that the mean annual leached total nitrogen loads from the HNHI,LNHI and LNLI treatments were 325,294 and 257 kg N ha^(–1) in the fluvo-aquic soil,114,100 and 78 kg N ha^(–1) in the cinnamon soil and 79,68 and 57 kg N ha^(–1) in the black soil,respectively.The N dissolved in irrigation water in the fluvo-aquic soil areas was 8.26-fold higher than in the cinnamon areas.A structural equation model showed that N fertiliser inputs and leaching water amounts explained 14.7 and 81.8%of the variation of leached N loads,respectively.Correspondingly,reducing irrigation water by 21.5%decreased leached N loads by 20.9%,while reducing manure N and chemical N inputs by 22 and 25%decreased leached N loads by only 9.5%. This study highlights that protected vegetable fields dominated by fluvo-aquic soil need management to curtail leached N losses in northern China.展开更多
Background:Animals need to adjust their vigilance strategies when foraging between physically contrasting veg-etated and non-vegetated habitats.Vegetated habitats may pose a greater risk for some if vegetation charact...Background:Animals need to adjust their vigilance strategies when foraging between physically contrasting veg-etated and non-vegetated habitats.Vegetated habitats may pose a greater risk for some if vegetation characteristics function as a visual obstruction but benefit others if they serve as protective shelter.Variation in group size,presence of similar species,along with variation in environmental conditions and anthropogenic disturbance can also influence vigilance investment.Methods:In this study,we quantified the vigilance behaviour of two large-bodied,sympatric migratory curlew species-Far Eastern Curlew(Numenius madagascariensis)and Eurasian Curlew(N.arquata)-in vegetated Suaeda salsa saltmarsh and non-vegetated mudflat habitat in Liaohekou National Nature Reserve,China.We used linear mixed models to examine the effects of habitat type,season,tide time,flock size(conspecific and heterospecific),and human disturbance on curlew vigilance investment.Results:Both species spent a higher percentage of time under visual obstruction in S.salsa habitat compared to mudflat habitat but in response,only Far Eastern Curlew increased their percentage of vigilance time,indicating that visual obstruction in this habitat is only a concern for this species.There was no evidence that S.salsa vegetation served as a form of cryptic background colouration since neither species decreased their vigilance effect in S.salsa habitat in spring compared to the autumn migration season.The effect of curlew social environment(i.e.flock size)was habitat dependent since percentage of vigilance time by curlews in saltmarsh increased with both the number of individual curlews and number of other birds present,but not in mudflat habitat.Conclusions:We conclude that both migratory curlew species exhibit a flexible vigilance adjustment strategy to cope with the different environmental and social conditions of adjacent and sharply contrasting coastal habitats,and that the trade-off between the risks of foraging and the abundance of prey may be a relatively common phenom-enon in these and other shorebird populations.展开更多
An investigation on environmental background values was made in an area of about 1,140,000 km2, which included temperate and subtropical zones of China. The environmental background values of 142 soil environment unit...An investigation on environmental background values was made in an area of about 1,140,000 km2, which included temperate and subtropical zones of China. The environmental background values of 142 soil environment units, 18 main soil types, 87 surface water environment units, 8 aquatic organism environment units and 20 underground water environment units were obtained. The rules, causes and effecting factors of regional differentiation of the environmental background values were deduced from over 200,000 various data.展开更多
Integrating disaster waste issue is a critical component of making humanitarian action fit for the future,anticipating global risks and challenges such as increased vulnerability due to climate change and environmenta...Integrating disaster waste issue is a critical component of making humanitarian action fit for the future,anticipating global risks and challenges such as increased vulnerability due to climate change and environmental degradation.This requires a fundamental shift towards a model that not only strengthens the response to crises but also learns and adapts in order to anticipate and act before such waste garnered.This article conducted analyses on the characteristics of disasters in the past two decades.Uncertainties confound disaster waste management,including the timing and magnitude of each disaster,and the amounts and types of waste that will be generated.For these reasons alone,disaster waste management must be an integral part of development planning and processes.Making 10 years since the 2008 Wenchuan earthquake,this article highlights that disaster waste management is not only debris clearance or waste management following a disaster,but also includes prevention and pre-disaster preparedness aspects in terms of enhancing resilience of local communities.Such"mainstreaming,"ensures that disaster waste management(DWM)will be treated as a priority issue,on an ongoing basis.Based on UN Environment's experiences and approaches,this paper emphasises that preparedness is the key,and that priority should be accorded to integrating disaster contingency planning in national and city level waste management strategies as well as mainstreaming waste management issues within broader disaster preparedness and response plans and actions.It is envisaged that the issues presented and the gaps identified in this paper will provide a basis for future comprehensive and cohesive research on disaster waste management.In turn,this research can lead to better preparedness and response on disaster waste management.展开更多
Phytoplankton communities can response immediately and directly to environmental changes,and thus have been applied as reliable biotic indicators in aquatic systems.This study provided insights into the relationships ...Phytoplankton communities can response immediately and directly to environmental changes,and thus have been applied as reliable biotic indicators in aquatic systems.This study provided insights into the relationships concerning ecological thresholds of phytoplankton communities and individual taxon in response to environmental changes in coastal waters of northern Zhejiang Province,East China Sea.Results demonstrated that there existed seasonal variations of phytoplankton community ecological thresholds of which spring being higher than those in summer.As for individual species,Prorocentrum donghaiense and Noctiluca scintillans were identified as the most tolerant and sensitive indicator species in spring and summer,respectively.They exhibited strong indications in response to environmental changes.These findings highlighted that phytoplankton community structure in this region was stable when environmental gradients were below the thresholds of sensitive species,whereas potential harmful algal blooms may occur when environmental gradients exceeded the thresholds of tolerant species.展开更多
Understanding the relative roles of local environmental effects and spatial effects on phytoplankton community is of essential importance to study the biogeography of them at regional scale. However, the determinants ...Understanding the relative roles of local environmental effects and spatial effects on phytoplankton community is of essential importance to study the biogeography of them at regional scale. However, the determinants that driving the biogeography of phytoplankton communities in the coastal area of northern Zhejiang still remained unclear. We surveyed phytoplankton community compositions in water columns associated with environmental and spatial influences across five subzones that geographically covering this region over four seasons. Diatoms and dinoflagellates were recorded as the main dominant groups and Coscinodiscus oculs-iridis, Coscinodiscus jonesianus, and Skeletonema costatum, were identified as the major abundant species existing in all seasons.Spatially structured environmental conditions, rather than pure spatial or environmental factors, substantially shaped the biogeography of phytoplankton community, with the former mainly comprised of water temperature,dissolved oxygen, phosphate, pH, and salinity, and the latter referring to a non-negligible factor. This study was the first integrated research that combining environmental filtering with spatial factors in structuring phytoplankton communities at a complete tempo-spatial scale. Our results may facilitate to the further study of harmful algal blooms early-warning in this region.展开更多
Based on the advantages of the openness,flexibility,high-efficiency,intelligence,and safety of grid,this paper focuses on the methods of marine environmental information sharing and integration in grid environment.Acc...Based on the advantages of the openness,flexibility,high-efficiency,intelligence,and safety of grid,this paper focuses on the methods of marine environmental information sharing and integration in grid environment.According to the characteristics of marine information,which includes multisource,dynamic,and high-dimensional,this paper provides a framework and the technical solution for a multisource marine environmental information grid platform.As an experiment,the prototype takes the region of South China Sea as its study area and chooses three kinds of marine environmental information as the representative types for the marine information.The realization of the prototype of multisource marine environmental information grid platform shows the feasibility and practicality of the framework and the technical solution.展开更多
The cave-site of Gruta da Furninha is a coastal karstic cavity. In the late 19th century, excavation of the sedimentary infill of the cave allowed the identification of two lithostratigraphic units： a Holocene one do...The cave-site of Gruta da Furninha is a coastal karstic cavity. In the late 19th century, excavation of the sedimentary infill of the cave allowed the identification of two lithostratigraphic units： a Holocene one dominated by sands, containing human bones and a Neolithic industry; and a Late Pleistocene one, containing a diverse set of fossils set and Paleolithic artifacts. This study mainly focuses on taphonomic and palaeoenvironmental data concerning the Pleistocene bird bones that were collected from six layers （at 11 m and 6.7 m asl）. A main result of this study was the discovery of a left humerus fragment, with osteological features of the Alcidae family; from comparison with upper arms of distinct species of this family, it was concluded that this fossil belongs to Penguin impennis. The Pleistocene birds of the Furninha cave were also compared with the avifauna that currently occurs in the region of Peniche peninsula and a climate and environmental interpretation of the Pleistocene fossiliferous set is provided.展开更多
Scientific knowledge on the chemical compositions of fine particulate matter(PM_(2.5)) is essential for properly assessing its health and climate effects,and for decisionmakers to develop efficient mitigation strategi...Scientific knowledge on the chemical compositions of fine particulate matter(PM_(2.5)) is essential for properly assessing its health and climate effects,and for decisionmakers to develop efficient mitigation strategies.A high-resolution PM_(2.5) chemical composition dataset(CAQRA-aerosol)is developed in this study,which provides hourly maps of organic carbon,black carbon,ammonium,nitrate,and sulfate in China from 2013 to 2020 with a horizontal resolution of 15 km.This paper describes the method,access,and validation results of this dataset.It shows that CAQRA-aerosol has good consistency with observations and achieves higher or comparable accuracy with previous PM_(2.5) composition datasets.Based on CAQRA-aerosol,spatiotemporal changes of different PM_(2.5) compositions were investigated from a national viewpoint,which emphasizes different changes of nitrate from other compositions.The estimated annual rate of population-weighted concentrations of nitrate is 0.23μg m^(−3)yr^(−1) from 2015 to 2020,compared with−0.19 to−1.1μg m^(−3)yr^(−1) for other compositions.The whole dataset is freely available from the China Air Pollution Data Center(https://doi.org/10.12423/capdb_PKU.2023.DA).展开更多
Occurrence and abundance of molecular hydrogen in natural geologic reservoirs are enigmatic,due to its various sources,diverse migration pathways and complicated biological and chemical reactions.Natural gas samples c...Occurrence and abundance of molecular hydrogen in natural geologic reservoirs are enigmatic,due to its various sources,diverse migration pathways and complicated biological and chemical reactions.Natural gas samples containing hydrogen from producing wells in several sedimentary basins in China were collected in this study,and gas abundances and isotopic compositions of these gases were compared with those in global petroliferous basins and deep intrusive rocks.Several geochemical indicators were suggested for identifying sources,migration and accumulation mechanisms of hydrogen in the subsurface environment.Hydrogen contents in natural gas deposits have contributions from various sources with the following high-to-low order:microbial degradation>serpentinization>deep mantle volatile release>radiation-induced water decomposition>thermal cracking of organic matter.A hydrogen-rich reservoir in Kansas,USA,is specifically analyzed to determine its formation mechanism.This study suggests that future exploration of geological hydrogen resources may focus on the igneous rock bodies with overlying dense sedimentary rocks in the continental rift systems.展开更多
Catastrophic failure in engineering structures of island reefs would occur when the tertiary creep initiates in coral reef limestone with a transition from short-to long-term load.Due to the complexity of biological s...Catastrophic failure in engineering structures of island reefs would occur when the tertiary creep initiates in coral reef limestone with a transition from short-to long-term load.Due to the complexity of biological structures,the underlying micro-behaviors involving time-dependent deformation are poorly understood.For this,an abnormal phenomenon was observed where the axial and lateral creep deformations were mutually independent by a series of triaxial tests under constant stress and strain rate conditions.The significantly large lateral creep deformation implies that the creep process cannot be described in continuum mechanics regime.Herein,it is hypothesized that sliding mechanism of crystal cleavages dominates the lateral creep deformation in coral reef limestone.Then,approaches of polarizing microscope(PM)and scanning electronic microscope(SEM)are utilized to validate the hypothesis.It shows that the sliding behavior of crystal cleavages combats with conventional creep micro-mechanisms at certain condition.The former is sensitive to time and strain rate,and is merely activated in the creep regime.展开更多
Acid-base dissociable antibiotic-metal complexes are known to be emerging contaminants in the aquatic environments.However,little information is available on the photochemical properties and toxicity of these complex ...Acid-base dissociable antibiotic-metal complexes are known to be emerging contaminants in the aquatic environments.However,little information is available on the photochemical properties and toxicity of these complex forms.This study investigated the spectral properties of three fluoroquinolones(FQs)with and without metal ions Fe(III),Cu(II),and Al(III)in solutions under different pH conditions,as well as evaluated the changes in toxicity due to the complex with thesemetal ions using luminescent bacteria(vibrio fischeri).FQs showed a higher tendency to coordinate metal ions under alkaline conditions compared to neutral and acidic conditions,and the formation of complexes weakened the ultravioletabsorbing ability of FQs.At pH=7.0,Cu(II)quenched the fluorescence intensity of FQs.Moreover,their Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy were explored,revealing that the coordination sites of Cu(II)in three FQs were situated in a bidentate manner through the oxygen atom of the deprotonated carboxyl group and cyclic carbonyl oxygen atom.This conclusion was further verified by the theory of molecular surface electrostatic potential.In addition,except for complexes of ciprofloxacin-metals,enhanced toxicity of FQs upon coordination with Fe(III)was observed,while reduced toxicity was found for coordination with Cu(II)and Al(III).These results are important for accurately evaluating the photochemical behavior and risk of these antibiotics in aquatic environments contaminated with metal ions.展开更多
Migratory insect pests tend to suddenly immigrate into new habitats over a short period to simultaneously lay eggs in clusters,resulting in gregarious larvae that cause severe damage to crops.These aggregated larvae c...Migratory insect pests tend to suddenly immigrate into new habitats over a short period to simultaneously lay eggs in clusters,resulting in gregarious larvae that cause severe damage to crops.These aggregated larvae can adapt well to various natural enemies and pathogens in their new habitats,but how their resistance might be enhanced and its immunological significance remain unknown.Here,we examined how infection by a pathogen and a parasitic fly affect the immune response and migratory behavior in two phases of the oriental armyworm,Mythimna separata,which differ dramatically in their flight capacity and fecundity.The gregarious larvae displayed greater resistance than solitary larvae to the challenges of both the entomopathogenic fungus Metarhizium anisopliae and the parasitoid Exorista civilis.In response to a challenge by M.anisopliae,gregarious larvae exhibited more pronounced increases in phenoloxidase(PO)activity and lysozyme activity than solitary larvae.Furthermore,in addition to the greater PO and lysozyme activities,the levels of dopamine and 5-hydroxytryptamine(5-HT)were also greater in challenged gregarious and solitary larvae.Injection of dopamine(or 5-HT)significantly enhanced PO activity,lysozyme activity,antibacterial activity and larval survival.Subsequently,there was a significant increase in the flight capacity of adults derived from gregarious larvae challenged by M.anisopliae;while no significant variation was observed in the adults from challenged solitary larvae.The preoviposition period,oviposition period and fecundity were not significantly affected by M.anisopliae,regardless of whether the larvae were gregarious or solitary.These results provide new insights into the relationship between migration and immunity in insects,and their behavior after immunization.展开更多
文摘A methodology for identifying volatile organic compounds （VOCs） and determining air quality of indoor air has been developed. The air samples are collected using pump samplers by the inhabitants when they perceive odorous and/or discomfort episodes. Glass multi-sorbent tubes are connected to the pump samplers for the retention of VOC. The analysis is performed by automatic thermal desorption （ATD） coupled with gas chromatography-mass spectrometry （GC/MS）. This methodology can be applied in cases of sick building syndrome （SBS） evaluation, in which building occupants experience a series of varied symptoms that appear to be linked to time spent in the building. Chemical pollutants concentrations （e.g., VOC） have been described to contribute to SBS. To exemplify the methodology, a qualitative determination and an evaluation of existing VOC were performed in a dwelling where the occupants experienced the SBS symptoms. Higher total VOC （TVOC） levels were detected during episodes in indoor air （1.33 ±1.53 mg/m^3） compared to outdoor air （0.71± 0.46 mg/m^3）. The concentrations of individual VOCs, such as ethanol, acetone, isopropanol, 1-butanol, acetic acid, acetonitrile and 1-methoxy-2-propanol, were also higher than the expected for a standard dwelling. The external source of VOC was found to be an undeclared activity of storage and manipulation of solvents located at the bottom of a contiguous building.
基金supported by a Natural Environment Research Council(NERC) Collaborative Awards in Science and Engineering (CASE) studentship(NE/EEA6549/1)
文摘Groundwater residence time is a fundamental property of groundwater to understand important hydrogeological issues,such as deriving sustainable abstraction volumes,or,the evolution of groundwater quality.The anthropogenic trace gases chlorofluorocarbons (CFC-11,CFC-12 and CFC-113) and sulphur hexafluoride (SF6) are ideal in this regard because they have been released globally at known rates and become dissolved in groundwater following Henry’s Law,integrating over large spatial (global) and temporal (decades) scales.The CFCs and SF6 are able to date groundwater up to w100 years old with the caveat of certain simplifying assumptions.However,the inversion of environmental tracer concentrations (CFCs and SF6) to derive groundwater age rests on the accurate determination of groundwater recharge parameters,namely temperature,elevation,salinity and excess air,in addition to resolving the potential for contamination,degradation and unsaturated zone effects.This review explores the fundamentals of CFC-11,CFC-12,CFC-113 and SF6 as environmental tracers of groundwater age and recommends complementary techniques throughout.Once this relatively simple and inexpensive technique has been used to determine initial concentrations at the recharge zone,setting the groundwater dating ‘clock’ to zero,this review then explores the meaning of groundwater ‘age’ in relation to measured environmental tracer concentrations.It is shown that the CFCs and SF6 may be applied to a wide-range of hydrogeological problems and suggests that environmental tracers are particularly powerful tools when integrated with numerical flow and transport models.
基金financial support by the National Key Research and Development Program of China (No. 2017YFB0702302)National Natural Science Foundation of China (Nos. 51671200, 51501201 and 51501204)
文摘This work investigated the influence of Sn and Mo on corrosion behavior of ferrite-pearlite steel in the simulated bottom plate environment of cargo oil tank. The results indicate that the corrosion rate of three ferrite-pearlite steels increased with extending the immersion time due to the continuous accumulation of the residual Fe3C. However, the addition of Sn or the combined addition of Sn and Mo could reduce the corrosion rate of Sn containing steel and Sn-Mo containing steel to 37.5% and 20% of that of carbon steel, respectively. Moreover, the cathodic reaction of Sn containing steel and Sn-Mo containing steel was always controlled by the charge transfer step during the whole immersion test, while that of carbon steel was gradually transformed into the diffusion-controlled process. These results were mainly related with the deposition of metallic Sn and Mo on the steel surface. The metallic Sn and Mo with uniform distribution restrained the galvanic effect through suppressing both the anodic dissolution of ferrite and cathodic hydrogen evolution reaction on the residual Fe3C.
基金financially supported by the National Natural Science Foundation of China (Nos. 51701222, U1867216 and 51471175)。
文摘The effects of bentonite content on the corrosion behavior of low carbon steel in 5 mM NaHCO3+ 1 mM NaCl + 1 mM Na2SO4 solution were investigated by electrochemical measurements combined with X-ray diffraction(XRD) and scanning electron microscopy(SEM). In the initial immersion stage, the cathodic process of low carbon steel corrosion was dominated by the reduction of dissolved oxygen, while it transformed to the reduction of ferric corrosion products with the immersion time. The presence of bentonite colloids could suppress the cathodic reduction of oxygen due to their barrier effect on the diffusion of oxygen. However, the barrier performance of bentonite layer was gradually deteriorated due to the coagulation and separation of bentonite colloids caused by the charge neutralization of iron corrosion products dissolved from the steel substrate. More bentonite colloids could maintain the barrier effect for a long time before it was deteriorated by the accumulation of corrosion products. Conversely,it could lose the performance completely, and the corrosion behavior of low carbon steel reverted to the same as that in the blank solution.
文摘China is the largest producer and consumer of hydrochlorofluorocarbons （HCFCs）, and the production of HCFC-22 accounts for more than 80% of all HCFCs. This paper concentrates on the residential air-conditioner industry and analyzes the environmental benefits of accelerating the phase-out of HCFC-22 in China. According to the comparison of the baseline and phase-out scenarios of HCFC-22, the findings show that using HC-290 （propane） as a refrigerant alternative will directly reduce the greenhouse effect, and indirectly reduce the emission of greenhouse gases due to a reduction in the electricity consumption. The comparison of two scenarios of HC-290 and HFC-410A refrigerant alternatives shows that the use of HC-290 refrigerant will produce significantly higher environmental benefits than the HFC-410A refrigerant.
基金supported by the National Key Research and Development Program of China(2021YFD1700900)the National Natural Science Foundation of China(31972519)+1 种基金the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(2060302-05-956-1)the Project for the Government’s Purchase Service,China(13210186)。
文摘Globally,sub-optimal use of nitrogen (N) fertiliser and elevated N irrigation groundwater have led to high leached nitrate (NO_(3)^(–)) losses from protected vegetable field systems.Optimising fertiliser and irrigation management in different soil types is crucial to reduce future N loads from such systems.The present 4-year study examined leached N loads from lysimeter monitoring arrays set up across 18 protected vegetable system sites encompassing the dominant soil types of northern China.The treatments applied at each field site were:1) a high N and high irrigation input treatment (HNHI);2) a low N but high irrigation input treatment (LNHI) and 3) a low N with low irrigation input treatment (LNLI).Results showed that the mean annual leached total nitrogen loads from the HNHI,LNHI and LNLI treatments were 325,294 and 257 kg N ha^(–1) in the fluvo-aquic soil,114,100 and 78 kg N ha^(–1) in the cinnamon soil and 79,68 and 57 kg N ha^(–1) in the black soil,respectively.The N dissolved in irrigation water in the fluvo-aquic soil areas was 8.26-fold higher than in the cinnamon areas.A structural equation model showed that N fertiliser inputs and leaching water amounts explained 14.7 and 81.8%of the variation of leached N loads,respectively.Correspondingly,reducing irrigation water by 21.5%decreased leached N loads by 20.9%,while reducing manure N and chemical N inputs by 22 and 25%decreased leached N loads by only 9.5%. This study highlights that protected vegetable fields dominated by fluvo-aquic soil need management to curtail leached N losses in northern China.
基金supported by National Key Research and Develop-ment Program of China(No.2017YFC1403500 to JL)National Natural Science Foundation of China(No.31911540468 and 31672316 to DL)+1 种基金non-profit Foundation of Marine Environment and Ecological Conservation of CNOOC(CF-MEEC/TR/2020-20 to ZZ)Natural Science Foundation of Liaoning Province of China(2019-MS-154 to DL).
文摘Background:Animals need to adjust their vigilance strategies when foraging between physically contrasting veg-etated and non-vegetated habitats.Vegetated habitats may pose a greater risk for some if vegetation characteristics function as a visual obstruction but benefit others if they serve as protective shelter.Variation in group size,presence of similar species,along with variation in environmental conditions and anthropogenic disturbance can also influence vigilance investment.Methods:In this study,we quantified the vigilance behaviour of two large-bodied,sympatric migratory curlew species-Far Eastern Curlew(Numenius madagascariensis)and Eurasian Curlew(N.arquata)-in vegetated Suaeda salsa saltmarsh and non-vegetated mudflat habitat in Liaohekou National Nature Reserve,China.We used linear mixed models to examine the effects of habitat type,season,tide time,flock size(conspecific and heterospecific),and human disturbance on curlew vigilance investment.Results:Both species spent a higher percentage of time under visual obstruction in S.salsa habitat compared to mudflat habitat but in response,only Far Eastern Curlew increased their percentage of vigilance time,indicating that visual obstruction in this habitat is only a concern for this species.There was no evidence that S.salsa vegetation served as a form of cryptic background colouration since neither species decreased their vigilance effect in S.salsa habitat in spring compared to the autumn migration season.The effect of curlew social environment(i.e.flock size)was habitat dependent since percentage of vigilance time by curlews in saltmarsh increased with both the number of individual curlews and number of other birds present,but not in mudflat habitat.Conclusions:We conclude that both migratory curlew species exhibit a flexible vigilance adjustment strategy to cope with the different environmental and social conditions of adjacent and sharply contrasting coastal habitats,and that the trade-off between the risks of foraging and the abundance of prey may be a relatively common phenom-enon in these and other shorebird populations.
文摘An investigation on environmental background values was made in an area of about 1,140,000 km2, which included temperate and subtropical zones of China. The environmental background values of 142 soil environment units, 18 main soil types, 87 surface water environment units, 8 aquatic organism environment units and 20 underground water environment units were obtained. The rules, causes and effecting factors of regional differentiation of the environmental background values were deduced from over 200,000 various data.
文摘Integrating disaster waste issue is a critical component of making humanitarian action fit for the future,anticipating global risks and challenges such as increased vulnerability due to climate change and environmental degradation.This requires a fundamental shift towards a model that not only strengthens the response to crises but also learns and adapts in order to anticipate and act before such waste garnered.This article conducted analyses on the characteristics of disasters in the past two decades.Uncertainties confound disaster waste management,including the timing and magnitude of each disaster,and the amounts and types of waste that will be generated.For these reasons alone,disaster waste management must be an integral part of development planning and processes.Making 10 years since the 2008 Wenchuan earthquake,this article highlights that disaster waste management is not only debris clearance or waste management following a disaster,but also includes prevention and pre-disaster preparedness aspects in terms of enhancing resilience of local communities.Such"mainstreaming,"ensures that disaster waste management(DWM)will be treated as a priority issue,on an ongoing basis.Based on UN Environment's experiences and approaches,this paper emphasises that preparedness is the key,and that priority should be accorded to integrating disaster contingency planning in national and city level waste management strategies as well as mainstreaming waste management issues within broader disaster preparedness and response plans and actions.It is envisaged that the issues presented and the gaps identified in this paper will provide a basis for future comprehensive and cohesive research on disaster waste management.In turn,this research can lead to better preparedness and response on disaster waste management.
基金The Quantitative Analysis of Distribution Pattern of Water Quality and Design of Monitoring Networks in Xiangshan Bay and its Adjacent Waters,Northern Coastal Zhejiang under contract No.15130401。
文摘Phytoplankton communities can response immediately and directly to environmental changes,and thus have been applied as reliable biotic indicators in aquatic systems.This study provided insights into the relationships concerning ecological thresholds of phytoplankton communities and individual taxon in response to environmental changes in coastal waters of northern Zhejiang Province,East China Sea.Results demonstrated that there existed seasonal variations of phytoplankton community ecological thresholds of which spring being higher than those in summer.As for individual species,Prorocentrum donghaiense and Noctiluca scintillans were identified as the most tolerant and sensitive indicator species in spring and summer,respectively.They exhibited strong indications in response to environmental changes.These findings highlighted that phytoplankton community structure in this region was stable when environmental gradients were below the thresholds of sensitive species,whereas potential harmful algal blooms may occur when environmental gradients exceeded the thresholds of tolerant species.
基金Ecological Restoration Cost Evaluation in Archipelago Ecosystems:A Case Study in Putuo,Zhoushan Archipelago,East China Sea.
文摘Understanding the relative roles of local environmental effects and spatial effects on phytoplankton community is of essential importance to study the biogeography of them at regional scale. However, the determinants that driving the biogeography of phytoplankton communities in the coastal area of northern Zhejiang still remained unclear. We surveyed phytoplankton community compositions in water columns associated with environmental and spatial influences across five subzones that geographically covering this region over four seasons. Diatoms and dinoflagellates were recorded as the main dominant groups and Coscinodiscus oculs-iridis, Coscinodiscus jonesianus, and Skeletonema costatum, were identified as the major abundant species existing in all seasons.Spatially structured environmental conditions, rather than pure spatial or environmental factors, substantially shaped the biogeography of phytoplankton community, with the former mainly comprised of water temperature,dissolved oxygen, phosphate, pH, and salinity, and the latter referring to a non-negligible factor. This study was the first integrated research that combining environmental filtering with spatial factors in structuring phytoplankton communities at a complete tempo-spatial scale. Our results may facilitate to the further study of harmful algal blooms early-warning in this region.
基金Supported by the National 863 Program of China (No.2009AA12Z148,No.2007AA092202)the Knowledge Innovation Project of Chinese Academy of Sciences (No.KZCX1-YW-12-04)
文摘Based on the advantages of the openness,flexibility,high-efficiency,intelligence,and safety of grid,this paper focuses on the methods of marine environmental information sharing and integration in grid environment.According to the characteristics of marine information,which includes multisource,dynamic,and high-dimensional,this paper provides a framework and the technical solution for a multisource marine environmental information grid platform.As an experiment,the prototype takes the region of South China Sea as its study area and chooses three kinds of marine environmental information as the representative types for the marine information.The realization of the prototype of multisource marine environmental information grid platform shows the feasibility and practicality of the framework and the technical solution.
文摘The cave-site of Gruta da Furninha is a coastal karstic cavity. In the late 19th century, excavation of the sedimentary infill of the cave allowed the identification of two lithostratigraphic units： a Holocene one dominated by sands, containing human bones and a Neolithic industry; and a Late Pleistocene one, containing a diverse set of fossils set and Paleolithic artifacts. This study mainly focuses on taphonomic and palaeoenvironmental data concerning the Pleistocene bird bones that were collected from six layers （at 11 m and 6.7 m asl）. A main result of this study was the discovery of a left humerus fragment, with osteological features of the Alcidae family; from comparison with upper arms of distinct species of this family, it was concluded that this fossil belongs to Penguin impennis. The Pleistocene birds of the Furninha cave were also compared with the avifauna that currently occurs in the region of Peniche peninsula and a climate and environmental interpretation of the Pleistocene fossiliferous set is provided.
基金support from the National Key Scientific and Technological Infrastructure project “Earth System Science Numerical Simulator Facility” (Earth Lab)sponsored by the National Natural Science Foundation of China (Grant Nos. 42175132, 92044303, and 42205119)+2 种基金the National Key R&D Program (Grant Nos. 2020YFA0607802 and 2022YFC3703003)the CAS Information Technology Program (Grant No. CAS-WX2021SF-0107-02)the fellowship of China Postdoctoral Science Foundation (Grant No. 2022M723093)
文摘Scientific knowledge on the chemical compositions of fine particulate matter(PM_(2.5)) is essential for properly assessing its health and climate effects,and for decisionmakers to develop efficient mitigation strategies.A high-resolution PM_(2.5) chemical composition dataset(CAQRA-aerosol)is developed in this study,which provides hourly maps of organic carbon,black carbon,ammonium,nitrate,and sulfate in China from 2013 to 2020 with a horizontal resolution of 15 km.This paper describes the method,access,and validation results of this dataset.It shows that CAQRA-aerosol has good consistency with observations and achieves higher or comparable accuracy with previous PM_(2.5) composition datasets.Based on CAQRA-aerosol,spatiotemporal changes of different PM_(2.5) compositions were investigated from a national viewpoint,which emphasizes different changes of nitrate from other compositions.The estimated annual rate of population-weighted concentrations of nitrate is 0.23μg m^(−3)yr^(−1) from 2015 to 2020,compared with−0.19 to−1.1μg m^(−3)yr^(−1) for other compositions.The whole dataset is freely available from the China Air Pollution Data Center(https://doi.org/10.12423/capdb_PKU.2023.DA).
基金supported by the National Natural Science Foundation of China(Nos.42488101,42141021,42172149,42172168,U2244209)the Tencent Foundation through the XPLORER PRIZE。
文摘Occurrence and abundance of molecular hydrogen in natural geologic reservoirs are enigmatic,due to its various sources,diverse migration pathways and complicated biological and chemical reactions.Natural gas samples containing hydrogen from producing wells in several sedimentary basins in China were collected in this study,and gas abundances and isotopic compositions of these gases were compared with those in global petroliferous basins and deep intrusive rocks.Several geochemical indicators were suggested for identifying sources,migration and accumulation mechanisms of hydrogen in the subsurface environment.Hydrogen contents in natural gas deposits have contributions from various sources with the following high-to-low order:microbial degradation>serpentinization>deep mantle volatile release>radiation-induced water decomposition>thermal cracking of organic matter.A hydrogen-rich reservoir in Kansas,USA,is specifically analyzed to determine its formation mechanism.This study suggests that future exploration of geological hydrogen resources may focus on the igneous rock bodies with overlying dense sedimentary rocks in the continental rift systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.41877267,41877260)the Priority Research Program of the Chinese Academy of Science(Grant No.XDA13010201).
文摘Catastrophic failure in engineering structures of island reefs would occur when the tertiary creep initiates in coral reef limestone with a transition from short-to long-term load.Due to the complexity of biological structures,the underlying micro-behaviors involving time-dependent deformation are poorly understood.For this,an abnormal phenomenon was observed where the axial and lateral creep deformations were mutually independent by a series of triaxial tests under constant stress and strain rate conditions.The significantly large lateral creep deformation implies that the creep process cannot be described in continuum mechanics regime.Herein,it is hypothesized that sliding mechanism of crystal cleavages dominates the lateral creep deformation in coral reef limestone.Then,approaches of polarizing microscope(PM)and scanning electronic microscope(SEM)are utilized to validate the hypothesis.It shows that the sliding behavior of crystal cleavages combats with conventional creep micro-mechanisms at certain condition.The former is sensitive to time and strain rate,and is merely activated in the creep regime.
基金supported by the National Natural Science Foundation of China(Nos.21976045 and 22076112)China Scholarship Council(CSC)Scholarship(Nos.202208610125 and 202308610123)+1 种基金Shaanxi Key Laboratory of Environmental Monitoring and Forewarning of Trace Pollutants(No.SHJKFJJ202318)the Key Research and Development Program of Shaanxi Province(No.2024SF-YBXM-567).
文摘Acid-base dissociable antibiotic-metal complexes are known to be emerging contaminants in the aquatic environments.However,little information is available on the photochemical properties and toxicity of these complex forms.This study investigated the spectral properties of three fluoroquinolones(FQs)with and without metal ions Fe(III),Cu(II),and Al(III)in solutions under different pH conditions,as well as evaluated the changes in toxicity due to the complex with thesemetal ions using luminescent bacteria(vibrio fischeri).FQs showed a higher tendency to coordinate metal ions under alkaline conditions compared to neutral and acidic conditions,and the formation of complexes weakened the ultravioletabsorbing ability of FQs.At pH=7.0,Cu(II)quenched the fluorescence intensity of FQs.Moreover,their Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy were explored,revealing that the coordination sites of Cu(II)in three FQs were situated in a bidentate manner through the oxygen atom of the deprotonated carboxyl group and cyclic carbonyl oxygen atom.This conclusion was further verified by the theory of molecular surface electrostatic potential.In addition,except for complexes of ciprofloxacin-metals,enhanced toxicity of FQs upon coordination with Fe(III)was observed,while reduced toxicity was found for coordination with Cu(II)and Al(III).These results are important for accurately evaluating the photochemical behavior and risk of these antibiotics in aquatic environments contaminated with metal ions.
基金supported by the National Key Research and Development Program of China(2022YFD1400600)the National Natural Science Foundation of China(32172397,32472540,31871951 and 31672019)+1 种基金the China Agriculture Research System of MOF and MARA(CARS-22)the Natural Science Foundation of Beijing,China(6172030)。
文摘Migratory insect pests tend to suddenly immigrate into new habitats over a short period to simultaneously lay eggs in clusters,resulting in gregarious larvae that cause severe damage to crops.These aggregated larvae can adapt well to various natural enemies and pathogens in their new habitats,but how their resistance might be enhanced and its immunological significance remain unknown.Here,we examined how infection by a pathogen and a parasitic fly affect the immune response and migratory behavior in two phases of the oriental armyworm,Mythimna separata,which differ dramatically in their flight capacity and fecundity.The gregarious larvae displayed greater resistance than solitary larvae to the challenges of both the entomopathogenic fungus Metarhizium anisopliae and the parasitoid Exorista civilis.In response to a challenge by M.anisopliae,gregarious larvae exhibited more pronounced increases in phenoloxidase(PO)activity and lysozyme activity than solitary larvae.Furthermore,in addition to the greater PO and lysozyme activities,the levels of dopamine and 5-hydroxytryptamine(5-HT)were also greater in challenged gregarious and solitary larvae.Injection of dopamine(or 5-HT)significantly enhanced PO activity,lysozyme activity,antibacterial activity and larval survival.Subsequently,there was a significant increase in the flight capacity of adults derived from gregarious larvae challenged by M.anisopliae;while no significant variation was observed in the adults from challenged solitary larvae.The preoviposition period,oviposition period and fecundity were not significantly affected by M.anisopliae,regardless of whether the larvae were gregarious or solitary.These results provide new insights into the relationship between migration and immunity in insects,and their behavior after immunization.
