In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural a...In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural and anthropogenic effects on marine aerosols optical properties,as well as the applicability of multi-satellite products and IMPROVE equation.The averaged aerosol optical depth(AOD500 nm)was 0.31±0.16 andÅngström exponent440–675 nm was 0.29±0.30.In offshore China,significant anthropogenic emissions affected the marine environment.In remote WPO,dust aerosols transported from northern China,Siberia,Central Asia,and those settling from the upper troposphere originating from north Africa,Arabian peninsula,and western India,were dominant.The spatial trends of AOD were opposite in the mid-latitude and southern seas of WPO.The highest AOD,0.32±0.23,appeared along the coast of South Asia at mid-latitude,decreasing from offshore seas to remote oceans.In low-latitude and equatorial seas,AOD significantly increased from coast to remote oceans.Ångström exponent dropped significantly from the coast to remote oceans as anthropogenic influence diminished across the entire WPO.Correlation analysis showed that both MODIS-C6 and Himawari AOD prod-ucts showed similar applicability in coastal urban areas,while Himawari AOD is highly recommended for coastal background and marine environment due to its finer resolution.The extinction coefficient derived from PM_(2.5) chemical compositions using IMPROVE algorithm exhibited a significant correlation(R^(2)=0.58)with the con-currently measured AOD in the absence of long-distance transport,suggesting that the IMPROVE is a reasonable proxy of the columnar average of marine aerosol extinctions free from transport influences.展开更多
Under severe sea conditions, wave slamming on ships and marine engineering structures may lead to structural damage and casualties. Moreover, the strong nonlinearity inherent in the wave slamming process significantly...Under severe sea conditions, wave slamming on ships and marine engineering structures may lead to structural damage and casualties. Moreover, the strong nonlinearity inherent in the wave slamming process significantly limits the accuracy of numerical analyses and finite element simulations. Therefore, this paper takes a new type of floating wind turbine as an example and performs a physical model test on the wave slamming characteristics of this floating wind turbine.Based on a 1:50 model of the Pivot Buoy floating wind turbine, an experimental study is performed under the combined effects of wind-wave loads on the peak pressure, duration, and pressure distribution of slamming. First, two sets of mooring systems, the combined scheme and the full mooring chain scheme, are designed to conduct a series of experimental studies of model slamming under different wind and wave incidence angles, wave heights, and wave periods. By doing so, the slamming characteristics of the wind turbine can be obtained. Moreover, to solve the problem of the large pitch motion response of the prototype wind turbine, a set of vertically oscillating structures is designed,and the slamming pressure characteristics of the optimized model are also investigated through model tests.展开更多
The numerical simulation of the fluid flow and the flexible rod(s)interaction is more complicated and has lower efficiency due to the high computational cost.In this paper,a semi-resolved model coupling the computatio...The numerical simulation of the fluid flow and the flexible rod(s)interaction is more complicated and has lower efficiency due to the high computational cost.In this paper,a semi-resolved model coupling the computational fluid dynamics and the flexible rod dynamics is proposed using a two-way domain expansion method.The gov-erning equations of the flexible rod dynamics are discretized and solved by the finite element method,and the fluid flow is simulated by the finite volume method.The interaction between fluids and solid rods is modeled by introducing body force terms into the momentum equations.Referred to the traditional semi-resolved numerical model,an anisotropic Gaussian kernel function method is proposed to specify the interactive forces between flu-ids and solid bodies for non-circle rod cross-sections.A benchmark of the flow passing around a single flexible plate with a rectangular cross-section is used to validate the algorithm.Focused on the engineering applications,a test case of a finite patch of cylinders is implemented to validate the accuracy and efficiency of the coupled model.展开更多
Sewage sludge in cities of Yangzi River Belt,China,generally exhibits a lower organic content and higher silt contentdue to leakage of drainage system,which caused low bioenergy recovery and carbon emission benefits i...Sewage sludge in cities of Yangzi River Belt,China,generally exhibits a lower organic content and higher silt contentdue to leakage of drainage system,which caused low bioenergy recovery and carbon emission benefits in conventional anaerobic digestion(CAD).Therefore,this paper is on a pilot scale,a bio-thermophilic pretreatment anaerobic digestion(BTPAD)for low organic sludge(volatile solids(VS)of 4%)was operated with a long-term continuous flow of 200 days.The VS degradation rate and CH_(4) yield of BTPAD increased by 19.93%and 53.33%,respectively,compared to those of CAD.The analysis of organic compositions in sludge revealed that BTPAD mainly improved the hydrolysis of proteins in sludge.Further analysis of microbial community proportions by high-throughput sequencing revealed that the short-term bio-thermophilic pretreatment was enriched in Clostridiales,Coprothermobacter and Gelria,was capable of hydrolyzing acidified proteins,and provided more volatile fatty acid(VFA)for the subsequent reaction.Biome combined with fluorescence quantitative polymerase chain reaction(PCR)analysis showed that the number of bacteria with high methanogenic capacity in BTPAD was much higher than that in CAD during the medium temperature digestion stage,indicating that short-term bio-thermophilic pretreatment could provide better methanogenic conditions for BTPAD.Furthermore,the greenhouse gas emission footprint analysis showed that short-term bio-thermophilic pretreatment could reduce the carbon emission of sludge anaerobic digestion system by 19.18%.展开更多
Surface wind speed(SWS)not only plays a crucial role in regulating the Earth's energy and hydrological cycle,but also is an important source of sustainable renewable energy.This study assesses the credibility of s...Surface wind speed(SWS)not only plays a crucial role in regulating the Earth's energy and hydrological cycle,but also is an important source of sustainable renewable energy.This study assesses the credibility of sws in three reanalyses(ERA5,MERRA2,and JRA-55)in East Asia using both satellite and in-situ observations.Results show all three reanalyses can capture the spatial pattern of swS as in observations,yet there are notable differences in magnitude.On land,ERA5 and MERRA2 overestimate the SWS by about 0.6 and 1.5 m s^(-1),respectively,whereas JRA-55 underestimates it.The biases over the oceans are opposite to those on land and are relatively small due to the assimilation of observations of oceanic surface winds.Overall,JRA-55 and ERA5 offer better estimates of seasonal means and variances of SWS than MERRA2.The observed SWS shows a negative trend of-0.08 m s^(-1)/10 yr on land and a positive trend of 0.09 m s^(-1)/10 yr in the western North Pacific.Only JRA-55 shows similar trends to observations over both land and ocean,while ERA5 and MERRA2 show varying degrees of deviation from the observations.Further investigation shows that there is a strong link between the trend of SWS and that of the large-scale circulation,and that a large part of the SwS trend can be attributed to changes in large-scale circulations.展开更多
The destabilization of overhanging rock is a dangerous geological problem.In this study,a generalized model of typical overhanging cliffs from the Three Gorges Reservoir area in China with different fracture angles,fr...The destabilization of overhanging rock is a dangerous geological problem.In this study,a generalized model of typical overhanging cliffs from the Three Gorges Reservoir area in China with different fracture angles,fracture lengths,and free surface depths is constructed to investigate the cracking and deformation behavior of overhanging rocks.Laboratory tests and deformation field monitoring using the digital image correlation(DIC)method are performed on these specimens to reproduce the destabilization and failure process of overhanging rock under external loading.The influence of peak load is found to be the most sensitive to the fracture length,followed by the free surface depth,and to be the least sensitive to the fracture angle.The DIC-based strain fields reveal that the fracture angle and free surface depth significantly alter the crack propagation paths,whereas the influence of the fracture length is weaker.These parameters also affect the crack initiation time.The relative displacement evolution characteristics indicate that fracture angle,fracture length,and free surface depth affect the shape and size of the rotating block,the rotation center,and the rotation pivot point and degree,respectively.The grayscale characteristic evolution trends are similar for all examined overhanging rock specimens.The evolution of the grayscale indices based on DIC can be divided into high-frequency oscillation,smooth decline(or smooth downward concavity),and stable development stages.Furthermore,the multistage properties of the indices can be used to identify the fracture state of overhanging rocks,providing a theoretical basis for graded early warning of rockfall disasters.展开更多
This study investigated the quasi-biweekly oscillation(QBWO)of the South Asian high(SAH)center in midsummer and its possible impact on rainfall in the middle and lower reaches of the Yangtze River Basin(MLYRB),using E...This study investigated the quasi-biweekly oscillation(QBWO)of the South Asian high(SAH)center in midsummer and its possible impact on rainfall in the middle and lower reaches of the Yangtze River Basin(MLYRB),using ERA5 reanalysis data and CPC(Climate Prediction Center)Global Unified Precipitation data from 1979-2023.First,associated with the phase evolution of the QBWO of the SAH center zonally,a general systematic westward propagation of a wave train pattern along the northern margin of the SAH can be identified.Second,energy analysis indicates that this wave train pattern gains energy from the basic flow through both barotropic and baroclinic energy conversion.Compared with barotropic energy conversion,baroclinic energy conversion plays the more important role in the growth,maintenance,and propagation of the wave train pattern associated with the QBWO of the SAH center.Third,the QBWO of the SAH center leads the variation in rainfall in the MLYRB by approximately four days,and might modulate the precipitation in the MLYRB by affecting the coupling of upper-and lower-level circulation anomalies over the MLYRB.The findings of this study suggest that the QBWO of the SAH center could act as potential source of predictability of intraseasonal variation in precipitation in the MLYRB.展开更多
[Objective] The study aimed to discuss the application of a stereo constructed wetland to the treatment of slightly polluted source water. [Method] In this study, a new stereo constructed wetland mode was put forward,...[Objective] The study aimed to discuss the application of a stereo constructed wetland to the treatment of slightly polluted source water. [Method] In this study, a new stereo constructed wetland mode was put forward, and a pilot project of water ecological purification in Xinsheng River, the diversion channel of Shijiuyang Waterwork in Jiaxing City, were analyzed. Afterwards, the impact factors of water purification by the technology were discussed from water quality and quantity, season and climate, species configuration, management and maintenance. [Result] Under three different hydraulic loading conditions, the pilot project effectively improved water SD and DO level, and reduced SS, CODCr, NH3-N, TN and TP significantly in summer and autumn, so that effluent water quality reached surface water standard at Grade III. [Conclusion] The stereo constructed wetland mode composed of constructed wetland and underwater forest used to treat slightly polluted source water is feasible and has a good promotion prospect.展开更多
Despite laboratory experiments that have been performed to study internal heavy metal release,our understanding of how heavy metals release in shallow eutrophic lakes remains limited for lacking in-situ evidence.This ...Despite laboratory experiments that have been performed to study internal heavy metal release,our understanding of how heavy metals release in shallow eutrophic lakes remains limited for lacking in-situ evidence.This study used automatic environmental sensors and a water sampling system to conduct high-frequency in-situ observations(1-hr intervals)of water environmental variables and to collect water samples(3-hr intervals),with which to examine the release of internal heavy metals in Lake Taihu,China.Under conditions of disturbance by strong northerly winds,sediment resuspension in both the estuary area and the lake center caused particulate heavy metal resuspension.However,the patterns of concentrations of dissolved heavy metals in these two areas were complex.The concentrations of dissolved Se and Mo increased in both areas,indicating that release of internal dissolved Se and Mo is triggered by sediment resuspension.The concentrations of dissolved Ni,Zn,As,Mn,Cu,V,and Co tended to increase in the estuary area but decrease in the lake center.The different trends between these two areas were controlled by pH and cyanobacteria,which are related to eutrophication.During the strong northerly winds,the decrease in concentrations of dissolved heavy metals in the lake center was attributable primarily to absorption by the increased suspended solids,and to growth-related assimilation or surface adsorption by the increased cyanobacteria.The findings of this study suggest that,short-term changes of environmental conditions are very important in relation to reliable monitoring and risk assessment of heavy metals in shallow eutrophic lakes.展开更多
Warm and ice-rich frozen soil(WIRFS) exhibits lower shear strength due to the weak binding forces between soil particles and ice crystals. To enhance the strength of WIRFS, frozen soil was treated separately with Port...Warm and ice-rich frozen soil(WIRFS) exhibits lower shear strength due to the weak binding forces between soil particles and ice crystals. To enhance the strength of WIRFS, frozen soil was treated separately with Portland, Phosphate, Sulphoaluminate, Portland-Phosphate and PortlandSulphoaluminate cements. After the samples were cured under -1.0°C for 7 days, the microscopic pore distribution characteristics and the macro-mechanical properties of WIRFS were investigated using mercury intrusion porosimetry(MIP), scanning electron microscopy(SEM) and unconfined compressive strength(UCS) tests. To quantitatively analyze the laws of pore-size transformation and the variation of Hausdorff volumetric fractal dimensions for pre-and post-treated WIRFS, the CURVEEXTRACT and Image-Pro Plus(IPP) image analysis system has been developed for analysing SEM images of the soil samples. Statistics of the pore-area dimension and pore-volume dimension were calculated. The results reveal that the cement-based treatment of WIRFS can improve the cementation fill of soil pores and the bond forces between soil particles. There is an evident correlation between the microstructure characteristics and the mechanical properties of the treated WIRFS. As the fractal dimensions of pore-area decrease, the unconfined compressive strength of cement-treated WIRFS increases significantly. In contrast, as the fractal dimensions of pore-volume increases, the unconfined compressive strength decreases remarkably.展开更多
Vertical distribution processes of sediment contaminants in water were studied by flume experiments. Experimental results show that settling velocity of sediment particles and turbulence characteristics are the major ...Vertical distribution processes of sediment contaminants in water were studied by flume experiments. Experimental results show that settling velocity of sediment particles and turbulence characteristics are the major hydrodynamic factors impacting distribution of pollutants, especially near the bottom where particle diameter is similar in size to vortex structure. Sediment distribution was uniform along the distance, while contaminant distribution slightly lagged behind the sediment. The smaller the initial sediment concentration was, the more time it took to achieve a uniform concentration distribution for suspended sediment. A contaminants transportation equation was established depending on mass conservation equations. Two mathematical estimation models of pollutant distribution in the overlying water considering adsorption and desorption were devised based on vertical distribution of suspended sediment: equilibrium partition model and dynamic micro-diffusion model. The ratio of time scale between the sediment movement and sorption can be used as the index of the models. When this ratio was large, the equilibrium assumption was reasonable, but when it was small, it might require dynamic micro-diffusion model.展开更多
Fulvic acid(FA),typical organic matter derived from humification process in composted sludge,possesses the potential to remediate mine soils contaminated by heavy metals.To understand the cooper(Cu)immobilizing proces...Fulvic acid(FA),typical organic matter derived from humification process in composted sludge,possesses the potential to remediate mine soils contaminated by heavy metals.To understand the cooper(Cu)immobilizing process in open-pit mine soil induced by FA,changes of Cu speciation in mixture of open-pit mine soil and composted sludge was tracked over 180 days.It was observed that the organic-bound and residual fraction of Cu increased dramatically with the corresponding decrease of Fe/Mn oxide-bound Cu in the first 60 days,then the organic-bound fraction decreased to about its initial proportion during 60-120 days,while residual fraction still increased,and the proportion of residual Cu accounted for over85%and became stable after 120 days.To reveal the mechanism of FA inducing Cu fixation on Albite which is the main phase of soil primary ore,two groups of Cu adsorption experiments with and without FA were designed.With the addition of FA,the adsorption capacity of Cu by Albite increased by 1.55 times and the content of residual Cu in Albite increased by7.7 times.It was found that the Cu absorbed in smaller Albite particle induced by FA formed a secondary mineral——Chrysocolla,causing increase of residual fraction of Cu.These results revealed the mechanism:FA was absorbed on the surface of Albite after complexing with Cu ions in the solution,and then it induced Cu into the interlayer and pore channels of Albite.The Cu in the Albite was immobilized by forming Chrysocolla finally.展开更多
Sludge is the by-product of wastewater treatment process. Multisource sludge can be defined as sludge from different sources. Based on the sludge properties of five typical cities in the Yangtze River basin, including...Sludge is the by-product of wastewater treatment process. Multisource sludge can be defined as sludge from different sources. Based on the sludge properties of five typical cities in the Yangtze River basin, including Jiujiang, Wuhu, Lu’an, Zhenjiang and Wuhan, this study investigated and summarized the characteristic variations and distribution differences of multiple indicators and substances from municipal sludge, dredged sludge, and river and lake sediments. The results demonstrated pH of multisource sludge was relatively stable in the neutral range. Organic matter and water content among municipal sludge were high and varied considerably between different wastewater treatment plants. Dredged sludge had an obviously higher sand content and wider particle distribution, which could be considered for graded utilization depending on its size. The nutrients composition of river and lake sediments was usually stable and special, with lower nitrogen and phosphorus content but higher potassium levels. The sources of heavy metals and persistent organic pollutants in multisource sludge were correlated, generally much higher among municipal sludge than dredged sludge and river and lake sediments, which were the most important limitation for final land utilization. Despite various properties of multisource sludge, the final fate and destination have some overall similarities, which need to be supplemented and improved by standards and laws. The study provided a preliminary analysis of suitable technical routes for municipal sludge, dredged sludge, river and lake sediments based on their different characteristics respectively, which was of great significance for multisource sludge co-treatment and disposal in the future of China.展开更多
Marine current energy has been increasingly used because of its predictable higher power potential.Owing to the external disturbances of various flow velocity and the high nonlinear effects on the marine current turbi...Marine current energy has been increasingly used because of its predictable higher power potential.Owing to the external disturbances of various flow velocity and the high nonlinear effects on the marine current turbine(MCT)system,the nonlinear controllers which rely on precise mathematical models show poor performance under a high level of parameters’uncertainties.This paper proposes an adaptive single neural control(ASNC)strategy for variable step-size perturb and observe(P&O)maximum power point tracking(MPPT)control.Firstly,to automatically update the neuron weights of SNC for the nonlinear systems,an adaptive mechanism is proposed to adaptively adjust the weighting and learning coefficients.Secondly,aiming to generate the exact reference speed for ASNC to extract the maximum power,a variable step-size law based on speed increment is designed to strike a balance between tracking speed and accuracy of P&O MPPT.The robust stability of the MCT control system is guaranteed by the Lyapunov theorem.Comparative simulation results show that this strategy has favorable adaptive performance under variable velocity conditions,and the MCT system operates at maximum power point steadily.展开更多
Thermally activated pinecone(TAP) was used for the adsorption of dimethyl trisulfide(DMTS)from aqueous solutions,which was proved to be the main odorous in algae-caused black bloom.The effects of adsorbent dosage,adso...Thermally activated pinecone(TAP) was used for the adsorption of dimethyl trisulfide(DMTS)from aqueous solutions,which was proved to be the main odorous in algae-caused black bloom.The effects of adsorbent dosage,adsorbate concentration and contact time on DMTS biosorption were studied.The TAP produced at 600℃ exhibited a relatively high surface area(519.69 m^2/g) and excellent adsorption capacity.The results show that the adsorption of DMTS was initially fast and that the equilibrium time was6 h.Higher initial DMTS concentrations led to lower removal percentages but higher adsorption capacity.The removal percentage of DMTS increased and the adsorption capacity of TAP decreased with an increase in adsorbent dosage.The adsorption process conforms well to a pseudo-second-order kinetics model.The adsorption of DMTS is more appropriately described by the Freundlich isotherm(R^2=0.996 1) than by the Langmuir isotherm(R^2=0.916 9).The results demonstrate that TAP could be an attractive low-cost adsorbent for removing DMTS from water.展开更多
Based on TM images,ArcGIS and landscape ecology,4 typical roads in the Pearl River Delta are taken for example to analyze infl uence range of highway,and study the laws of highway construction infl uencing landscape p...Based on TM images,ArcGIS and landscape ecology,4 typical roads in the Pearl River Delta are taken for example to analyze infl uence range of highway,and study the laws of highway construction infl uencing landscape patterns by reviewing landscape pattern changes in areas along the highways. According to the research,for Yuebei Section(north Guangdong) of Beijing–Zhuhai Highway,road construction has signifi cant infl uence on landscape patterns of the 300-m wide buffer zone(especially woodland and urban land); for Foshan–Kaiping Highway,road construction has significant influence on landscape patterns of the 1,000-m wide buffer zone(especially woodland and agricultural land); for Dongguan–Shenzhen Highway,road construction has signifi cant infl uence on landscape patterns of the 8,000-m wide buffer zone(especially woodland and urban land).展开更多
Previous study found that the pre-treatment of sewage sludge with nitrite improves the biogas production during the mono/two-phase anaerobic digestion (AD) using batch biochemical methane potential tests.In this study...Previous study found that the pre-treatment of sewage sludge with nitrite improves the biogas production during the mono/two-phase anaerobic digestion (AD) using batch biochemical methane potential tests.In this study,the effects of nitrite on hydrolysisacidification,biogas production,volatile solids destruction and microbial composition in semi-continuous two-phase AD of sewage sludge were investigated.The addition of nitrite promotes sludge organic matter solubilization (+484%) and VFAs production (+98.9%),and causes an increase in the VS degradation rate during the AD process (+8.7%).The comparison of biogas production from the acidogenic and methanogenic reactors with or without the addition of nitrite implies that the nitrite has no significant effect on the overall biogas production of two-phase sludge AD process.High-throughput sequencing analysis shows that the microbial communities of bacteria and archaea in two-phase AD reactors significantly changes after the addition of nitrite.Vulcanibacillus (bacteria) and Candidatus Methanofastidiosum (archaea) become the dominant genera in the acidogenic and methanogenic reactors with the nitrite respectively.These findings provide new insights about using nitrite to promote the organic matter degradation of sewage sludge in a semicontinuous two-phase AD system.展开更多
In recent years,the exploitation of offshore wind resources has been attached with greater importance.As a result,semi-submersible floating wind turbines(FWTs)have gradually become a popular research topic,with the st...In recent years,the exploitation of offshore wind resources has been attached with greater importance.As a result,semi-submersible floating wind turbines(FWTs)have gradually become a popular research topic,with the structural strength being a research hotspot as it can ensure the safe operation of FWTs.The severe sea conditions of freak waves result in enormous wave heights,extremely fast wave speeds,and concentrated energy.Thus,it is difficult to accurately simulate these effects on the loads of floating wind turbines using the potential flow theory and other theories.In this paper,the structural strength of a floating wind turbine under the action of freak waves is analyzed based on the CFD-FEA coupled method.The effects of the mooring system and the wind load are considered in the time domain,and the CFD method is applied to analyze the wave load of the floating wind turbine under the extreme sea state of freak waves.The strength and motion of the floating wind turbine float structure are analyzed by combining the CFD method and the FEA method,and the analytical results of the mutual transfer of these two methods are taken as the initial quantities for further analysis.The accuracy of the analytical model of the CFD-FEA method is verified by the results of the tank test analysis,and the structural strength analysis under freak wave conditions is carried out for a new type of floating wind turbine.The results of this research provide useful guidance and references for the design and engineering applications of offshore floating wind turbines.展开更多
Chemical analysis of groundwater in petroliferous basins can be an effective way to determine the regional hydrogeological regime and to evaluate the preservation conditions of hydrocarbons. This paper presents the hy...Chemical analysis of groundwater in petroliferous basins can be an effective way to determine the regional hydrogeological regime and to evaluate the preservation conditions of hydrocarbons. This paper presents the hydrochemical distribution of both individual aquifers and different structural units within the Palaeogene strata of the Gaoyou subbasin in the North Jiangsu Basin, east China. The results show that the salinity of the Palaeogene aquifers in the Gaoyou subbasin displays a systematic increase from the central deep depression to the periphery areas, and shows a reverse trend as the burial depth increases. Salinity maps of individual aquifers suggest that formation water in the deep layers at the centre of the study area probably retains original features of fresh lake water. Geofluids near the central deep depression of the Gaoyou subbasin migrate vertically through the Zhenwu and Hanliu faults, while those of the northern slope belt mainly flow laterally through aquifers. Both low and high salinity formation water can be found in the hydrocarbon producing areas. The low salinity zones commonly affected by infiltrated meteoric water are unfavourable conditions for the preservation of trapped hydrocarbons.展开更多
[Objective] The research aimed to study key problems of a new environmental dredging based on ecological protection and subsequent ecological restoration. [Method] People paid more attention to sediment pollutant remo...[Objective] The research aimed to study key problems of a new environmental dredging based on ecological protection and subsequent ecological restoration. [Method] People paid more attention to sediment pollutant removal in environmental dredging, without considering coming aquatic eco-restoration work after dredging. Factor affecting aquatic ecosystem existence and growth was screened, and ecological dredging manner was put forward. [Result] On the basis of analyzing dredging objective, effect and influence, started from ecological protection and subsequent ecological restoration, water depth and substrate were screened as priority control factors of the environmental sediment dredging. New manner of combining sediment dredging to reshape underwater terrain was put forward. [Conclusion] The research provided solution for water depth and substrate demands of the subsequent ecological restoration.展开更多
基金supported by the CAS Strategic Priority Research Program(No.XDB0760102),the Ministry of Science and Technology of China(No.2022YFF0802501)the Major Science and Technology Infrastructure Maintenance and Transformation Project of the Chinese Academy of Sciences,Shanghai Science and Technology Innovation Action Plan-Phospherus Project(No.23YF1426200)the National Key Research and Development Program of China(No.2024YFE0212200).
文摘In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural and anthropogenic effects on marine aerosols optical properties,as well as the applicability of multi-satellite products and IMPROVE equation.The averaged aerosol optical depth(AOD500 nm)was 0.31±0.16 andÅngström exponent440–675 nm was 0.29±0.30.In offshore China,significant anthropogenic emissions affected the marine environment.In remote WPO,dust aerosols transported from northern China,Siberia,Central Asia,and those settling from the upper troposphere originating from north Africa,Arabian peninsula,and western India,were dominant.The spatial trends of AOD were opposite in the mid-latitude and southern seas of WPO.The highest AOD,0.32±0.23,appeared along the coast of South Asia at mid-latitude,decreasing from offshore seas to remote oceans.In low-latitude and equatorial seas,AOD significantly increased from coast to remote oceans.Ångström exponent dropped significantly from the coast to remote oceans as anthropogenic influence diminished across the entire WPO.Correlation analysis showed that both MODIS-C6 and Himawari AOD prod-ucts showed similar applicability in coastal urban areas,while Himawari AOD is highly recommended for coastal background and marine environment due to its finer resolution.The extinction coefficient derived from PM_(2.5) chemical compositions using IMPROVE algorithm exhibited a significant correlation(R^(2)=0.58)with the con-currently measured AOD in the absence of long-distance transport,suggesting that the IMPROVE is a reasonable proxy of the columnar average of marine aerosol extinctions free from transport influences.
基金financially supported by the National Natural Science Foundation of China (Grant No. 52071161)。
文摘Under severe sea conditions, wave slamming on ships and marine engineering structures may lead to structural damage and casualties. Moreover, the strong nonlinearity inherent in the wave slamming process significantly limits the accuracy of numerical analyses and finite element simulations. Therefore, this paper takes a new type of floating wind turbine as an example and performs a physical model test on the wave slamming characteristics of this floating wind turbine.Based on a 1:50 model of the Pivot Buoy floating wind turbine, an experimental study is performed under the combined effects of wind-wave loads on the peak pressure, duration, and pressure distribution of slamming. First, two sets of mooring systems, the combined scheme and the full mooring chain scheme, are designed to conduct a series of experimental studies of model slamming under different wind and wave incidence angles, wave heights, and wave periods. By doing so, the slamming characteristics of the wind turbine can be obtained. Moreover, to solve the problem of the large pitch motion response of the prototype wind turbine, a set of vertically oscillating structures is designed,and the slamming pressure characteristics of the optimized model are also investigated through model tests.
基金supported by Shanghai 2021“Science and Technology Innovation Action Plan”:Social Development Science and Technology Research Project(Grant No.21DZ1202703).
文摘The numerical simulation of the fluid flow and the flexible rod(s)interaction is more complicated and has lower efficiency due to the high computational cost.In this paper,a semi-resolved model coupling the computational fluid dynamics and the flexible rod dynamics is proposed using a two-way domain expansion method.The gov-erning equations of the flexible rod dynamics are discretized and solved by the finite element method,and the fluid flow is simulated by the finite volume method.The interaction between fluids and solid rods is modeled by introducing body force terms into the momentum equations.Referred to the traditional semi-resolved numerical model,an anisotropic Gaussian kernel function method is proposed to specify the interactive forces between flu-ids and solid bodies for non-circle rod cross-sections.A benchmark of the flow passing around a single flexible plate with a rectangular cross-section is used to validate the algorithm.Focused on the engineering applications,a test case of a finite patch of cylinders is implemented to validate the accuracy and efficiency of the coupled model.
基金supported by the National Key Research and Development Project (Nos.2020YFC1908702 and 2021YFC3200700)the National Natural Science Foundation of China (Nos.52192684 and 52192680).
文摘Sewage sludge in cities of Yangzi River Belt,China,generally exhibits a lower organic content and higher silt contentdue to leakage of drainage system,which caused low bioenergy recovery and carbon emission benefits in conventional anaerobic digestion(CAD).Therefore,this paper is on a pilot scale,a bio-thermophilic pretreatment anaerobic digestion(BTPAD)for low organic sludge(volatile solids(VS)of 4%)was operated with a long-term continuous flow of 200 days.The VS degradation rate and CH_(4) yield of BTPAD increased by 19.93%and 53.33%,respectively,compared to those of CAD.The analysis of organic compositions in sludge revealed that BTPAD mainly improved the hydrolysis of proteins in sludge.Further analysis of microbial community proportions by high-throughput sequencing revealed that the short-term bio-thermophilic pretreatment was enriched in Clostridiales,Coprothermobacter and Gelria,was capable of hydrolyzing acidified proteins,and provided more volatile fatty acid(VFA)for the subsequent reaction.Biome combined with fluorescence quantitative polymerase chain reaction(PCR)analysis showed that the number of bacteria with high methanogenic capacity in BTPAD was much higher than that in CAD during the medium temperature digestion stage,indicating that short-term bio-thermophilic pretreatment could provide better methanogenic conditions for BTPAD.Furthermore,the greenhouse gas emission footprint analysis showed that short-term bio-thermophilic pretreatment could reduce the carbon emission of sludge anaerobic digestion system by 19.18%.
基金supported by the National Natural Science Foundation of China[grant numbers 42361144708,42205041,and 42175165]a scientific research project of the Shanghai Investigation,Design and Research Institute Co.,Ltd.[grant number 2023CN(83)-001]the National Key Scientific and Technological Infrastructure project“Earth System Science Numerical Simulator Facility”(EarthLab).
文摘Surface wind speed(SWS)not only plays a crucial role in regulating the Earth's energy and hydrological cycle,but also is an important source of sustainable renewable energy.This study assesses the credibility of sws in three reanalyses(ERA5,MERRA2,and JRA-55)in East Asia using both satellite and in-situ observations.Results show all three reanalyses can capture the spatial pattern of swS as in observations,yet there are notable differences in magnitude.On land,ERA5 and MERRA2 overestimate the SWS by about 0.6 and 1.5 m s^(-1),respectively,whereas JRA-55 underestimates it.The biases over the oceans are opposite to those on land and are relatively small due to the assimilation of observations of oceanic surface winds.Overall,JRA-55 and ERA5 offer better estimates of seasonal means and variances of SWS than MERRA2.The observed SWS shows a negative trend of-0.08 m s^(-1)/10 yr on land and a positive trend of 0.09 m s^(-1)/10 yr in the western North Pacific.Only JRA-55 shows similar trends to observations over both land and ocean,while ERA5 and MERRA2 show varying degrees of deviation from the observations.Further investigation shows that there is a strong link between the trend of SWS and that of the large-scale circulation,and that a large part of the SwS trend can be attributed to changes in large-scale circulations.
基金supported by the China National Natural Science Foundation(Grant No.42362034)the Applied Basic Research Foundation of Yunnan Province,China(Grant No.202401AS070068).
文摘The destabilization of overhanging rock is a dangerous geological problem.In this study,a generalized model of typical overhanging cliffs from the Three Gorges Reservoir area in China with different fracture angles,fracture lengths,and free surface depths is constructed to investigate the cracking and deformation behavior of overhanging rocks.Laboratory tests and deformation field monitoring using the digital image correlation(DIC)method are performed on these specimens to reproduce the destabilization and failure process of overhanging rock under external loading.The influence of peak load is found to be the most sensitive to the fracture length,followed by the free surface depth,and to be the least sensitive to the fracture angle.The DIC-based strain fields reveal that the fracture angle and free surface depth significantly alter the crack propagation paths,whereas the influence of the fracture length is weaker.These parameters also affect the crack initiation time.The relative displacement evolution characteristics indicate that fracture angle,fracture length,and free surface depth affect the shape and size of the rotating block,the rotation center,and the rotation pivot point and degree,respectively.The grayscale characteristic evolution trends are similar for all examined overhanging rock specimens.The evolution of the grayscale indices based on DIC can be divided into high-frequency oscillation,smooth decline(or smooth downward concavity),and stable development stages.Furthermore,the multistage properties of the indices can be used to identify the fracture state of overhanging rocks,providing a theoretical basis for graded early warning of rockfall disasters.
基金supported jointly by the National Natural Science Foundation of China(Grant No.42105039)the China Postdoctoral Science Foundation(Grant No.2024M753587)+4 种基金the Hubei Provincial Natural Science Foundation and Meteorological Innovation and development Joint Foundation of China(Grant No.2023AFD104)the Shanghai Science and Technology Development Funds(Grant No.24QB2703600)the Open Project Fund of the China Meteorological Administration Basin Heavy Rainfall Key Laboratory(Grant No.2023BHR-Y03)the Basic Research Fund of the Institute of Heavy Rain,China Meteorological Administration,Wuhan(Grant No.202314)the Open Project Fund of the Key Open Laboratory of Hydrometeorology,China Meteorological Administration(Grant No.23SWQXM018)。
文摘This study investigated the quasi-biweekly oscillation(QBWO)of the South Asian high(SAH)center in midsummer and its possible impact on rainfall in the middle and lower reaches of the Yangtze River Basin(MLYRB),using ERA5 reanalysis data and CPC(Climate Prediction Center)Global Unified Precipitation data from 1979-2023.First,associated with the phase evolution of the QBWO of the SAH center zonally,a general systematic westward propagation of a wave train pattern along the northern margin of the SAH can be identified.Second,energy analysis indicates that this wave train pattern gains energy from the basic flow through both barotropic and baroclinic energy conversion.Compared with barotropic energy conversion,baroclinic energy conversion plays the more important role in the growth,maintenance,and propagation of the wave train pattern associated with the QBWO of the SAH center.Third,the QBWO of the SAH center leads the variation in rainfall in the MLYRB by approximately four days,and might modulate the precipitation in the MLYRB by affecting the coupling of upper-and lower-level circulation anomalies over the MLYRB.The findings of this study suggest that the QBWO of the SAH center could act as potential source of predictability of intraseasonal variation in precipitation in the MLYRB.
基金Supported by National Science and Technology Project of Water Pollution Control and Management(2008ZX07421-001)
文摘[Objective] The study aimed to discuss the application of a stereo constructed wetland to the treatment of slightly polluted source water. [Method] In this study, a new stereo constructed wetland mode was put forward, and a pilot project of water ecological purification in Xinsheng River, the diversion channel of Shijiuyang Waterwork in Jiaxing City, were analyzed. Afterwards, the impact factors of water purification by the technology were discussed from water quality and quantity, season and climate, species configuration, management and maintenance. [Result] Under three different hydraulic loading conditions, the pilot project effectively improved water SD and DO level, and reduced SS, CODCr, NH3-N, TN and TP significantly in summer and autumn, so that effluent water quality reached surface water standard at Grade III. [Conclusion] The stereo constructed wetland mode composed of constructed wetland and underwater forest used to treat slightly polluted source water is feasible and has a good promotion prospect.
基金supported by the National Key R&D Program of China(No.2017YFC0405205)the National Natural Science Foundation of China(Nos.41971047,41621002,41661134036,41301531)+1 种基金the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(No.QYZDJ-SSW-DQC008)the“One-Three-Five”Strategic Planning of the Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences(No.NIGLAS2017GH04)。
文摘Despite laboratory experiments that have been performed to study internal heavy metal release,our understanding of how heavy metals release in shallow eutrophic lakes remains limited for lacking in-situ evidence.This study used automatic environmental sensors and a water sampling system to conduct high-frequency in-situ observations(1-hr intervals)of water environmental variables and to collect water samples(3-hr intervals),with which to examine the release of internal heavy metals in Lake Taihu,China.Under conditions of disturbance by strong northerly winds,sediment resuspension in both the estuary area and the lake center caused particulate heavy metal resuspension.However,the patterns of concentrations of dissolved heavy metals in these two areas were complex.The concentrations of dissolved Se and Mo increased in both areas,indicating that release of internal dissolved Se and Mo is triggered by sediment resuspension.The concentrations of dissolved Ni,Zn,As,Mn,Cu,V,and Co tended to increase in the estuary area but decrease in the lake center.The different trends between these two areas were controlled by pH and cyanobacteria,which are related to eutrophication.During the strong northerly winds,the decrease in concentrations of dissolved heavy metals in the lake center was attributable primarily to absorption by the increased suspended solids,and to growth-related assimilation or surface adsorption by the increased cyanobacteria.The findings of this study suggest that,short-term changes of environmental conditions are very important in relation to reliable monitoring and risk assessment of heavy metals in shallow eutrophic lakes.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41471062 and 41401087)the State Key Laboratory of Frozen Soil Engineering (Grant No.SKLFSE-ZT-35)
文摘Warm and ice-rich frozen soil(WIRFS) exhibits lower shear strength due to the weak binding forces between soil particles and ice crystals. To enhance the strength of WIRFS, frozen soil was treated separately with Portland, Phosphate, Sulphoaluminate, Portland-Phosphate and PortlandSulphoaluminate cements. After the samples were cured under -1.0°C for 7 days, the microscopic pore distribution characteristics and the macro-mechanical properties of WIRFS were investigated using mercury intrusion porosimetry(MIP), scanning electron microscopy(SEM) and unconfined compressive strength(UCS) tests. To quantitatively analyze the laws of pore-size transformation and the variation of Hausdorff volumetric fractal dimensions for pre-and post-treated WIRFS, the CURVEEXTRACT and Image-Pro Plus(IPP) image analysis system has been developed for analysing SEM images of the soil samples. Statistics of the pore-area dimension and pore-volume dimension were calculated. The results reveal that the cement-based treatment of WIRFS can improve the cementation fill of soil pores and the bond forces between soil particles. There is an evident correlation between the microstructure characteristics and the mechanical properties of the treated WIRFS. As the fractal dimensions of pore-area decrease, the unconfined compressive strength of cement-treated WIRFS increases significantly. In contrast, as the fractal dimensions of pore-volume increases, the unconfined compressive strength decreases remarkably.
基金supported by the National Natural Science Foundation of China (Grant 11502138)the National Key Research and Development Program (Grant 2016YFC0401500)the National Water Pollution Control and Treatment Science and Technology Major Project (Grant 2012ZX07506-002b)
文摘Vertical distribution processes of sediment contaminants in water were studied by flume experiments. Experimental results show that settling velocity of sediment particles and turbulence characteristics are the major hydrodynamic factors impacting distribution of pollutants, especially near the bottom where particle diameter is similar in size to vortex structure. Sediment distribution was uniform along the distance, while contaminant distribution slightly lagged behind the sediment. The smaller the initial sediment concentration was, the more time it took to achieve a uniform concentration distribution for suspended sediment. A contaminants transportation equation was established depending on mass conservation equations. Two mathematical estimation models of pollutant distribution in the overlying water considering adsorption and desorption were devised based on vertical distribution of suspended sediment: equilibrium partition model and dynamic micro-diffusion model. The ratio of time scale between the sediment movement and sorption can be used as the index of the models. When this ratio was large, the equilibrium assumption was reasonable, but when it was small, it might require dynamic micro-diffusion model.
基金supported by the Major Consulting Research Project of Chinese Academy of Engineering 2019-ZD-33projects from the China Three Gorges Group Co.LTD(No.2020(W)-080,No.202003065)。
文摘Fulvic acid(FA),typical organic matter derived from humification process in composted sludge,possesses the potential to remediate mine soils contaminated by heavy metals.To understand the cooper(Cu)immobilizing process in open-pit mine soil induced by FA,changes of Cu speciation in mixture of open-pit mine soil and composted sludge was tracked over 180 days.It was observed that the organic-bound and residual fraction of Cu increased dramatically with the corresponding decrease of Fe/Mn oxide-bound Cu in the first 60 days,then the organic-bound fraction decreased to about its initial proportion during 60-120 days,while residual fraction still increased,and the proportion of residual Cu accounted for over85%and became stable after 120 days.To reveal the mechanism of FA inducing Cu fixation on Albite which is the main phase of soil primary ore,two groups of Cu adsorption experiments with and without FA were designed.With the addition of FA,the adsorption capacity of Cu by Albite increased by 1.55 times and the content of residual Cu in Albite increased by7.7 times.It was found that the Cu absorbed in smaller Albite particle induced by FA formed a secondary mineral——Chrysocolla,causing increase of residual fraction of Cu.These results revealed the mechanism:FA was absorbed on the surface of Albite after complexing with Cu ions in the solution,and then it induced Cu into the interlayer and pore channels of Albite.The Cu in the Albite was immobilized by forming Chrysocolla finally.
基金supported by the Scientific Research Project of China Three Gorges Corporation, China (No. 202003081)the National Key Research and Development Program of China (No. 2020YFC1908702)the National Natural Science Foundation of China (NSFC) (No. 52131002)。
文摘Sludge is the by-product of wastewater treatment process. Multisource sludge can be defined as sludge from different sources. Based on the sludge properties of five typical cities in the Yangtze River basin, including Jiujiang, Wuhu, Lu’an, Zhenjiang and Wuhan, this study investigated and summarized the characteristic variations and distribution differences of multiple indicators and substances from municipal sludge, dredged sludge, and river and lake sediments. The results demonstrated pH of multisource sludge was relatively stable in the neutral range. Organic matter and water content among municipal sludge were high and varied considerably between different wastewater treatment plants. Dredged sludge had an obviously higher sand content and wider particle distribution, which could be considered for graded utilization depending on its size. The nutrients composition of river and lake sediments was usually stable and special, with lower nitrogen and phosphorus content but higher potassium levels. The sources of heavy metals and persistent organic pollutants in multisource sludge were correlated, generally much higher among municipal sludge than dredged sludge and river and lake sediments, which were the most important limitation for final land utilization. Despite various properties of multisource sludge, the final fate and destination have some overall similarities, which need to be supplemented and improved by standards and laws. The study provided a preliminary analysis of suitable technical routes for municipal sludge, dredged sludge, river and lake sediments based on their different characteristics respectively, which was of great significance for multisource sludge co-treatment and disposal in the future of China.
基金financially supported by the National Natural Science Foundation of China(Grant No.61673260)。
文摘Marine current energy has been increasingly used because of its predictable higher power potential.Owing to the external disturbances of various flow velocity and the high nonlinear effects on the marine current turbine(MCT)system,the nonlinear controllers which rely on precise mathematical models show poor performance under a high level of parameters’uncertainties.This paper proposes an adaptive single neural control(ASNC)strategy for variable step-size perturb and observe(P&O)maximum power point tracking(MPPT)control.Firstly,to automatically update the neuron weights of SNC for the nonlinear systems,an adaptive mechanism is proposed to adaptively adjust the weighting and learning coefficients.Secondly,aiming to generate the exact reference speed for ASNC to extract the maximum power,a variable step-size law based on speed increment is designed to strike a balance between tracking speed and accuracy of P&O MPPT.The robust stability of the MCT control system is guaranteed by the Lyapunov theorem.Comparative simulation results show that this strategy has favorable adaptive performance under variable velocity conditions,and the MCT system operates at maximum power point steadily.
基金Supported by the Taihu Special Project of Water Pollution Control,Jiangsu Province(No.TH2013214)the National Water Pollution Control and Management Technology Major Project(No.2012ZX07103-005)+1 种基金the Industry-Academia Cooperation Innovation Fund Project of Jiangsu Province(No.BY2011165)the Open Foundation of State Key Laboratory of Lake Science and Environment,CAS(No.2014SKL005)
文摘Thermally activated pinecone(TAP) was used for the adsorption of dimethyl trisulfide(DMTS)from aqueous solutions,which was proved to be the main odorous in algae-caused black bloom.The effects of adsorbent dosage,adsorbate concentration and contact time on DMTS biosorption were studied.The TAP produced at 600℃ exhibited a relatively high surface area(519.69 m^2/g) and excellent adsorption capacity.The results show that the adsorption of DMTS was initially fast and that the equilibrium time was6 h.Higher initial DMTS concentrations led to lower removal percentages but higher adsorption capacity.The removal percentage of DMTS increased and the adsorption capacity of TAP decreased with an increase in adsorbent dosage.The adsorption process conforms well to a pseudo-second-order kinetics model.The adsorption of DMTS is more appropriately described by the Freundlich isotherm(R^2=0.996 1) than by the Langmuir isotherm(R^2=0.916 9).The results demonstrate that TAP could be an attractive low-cost adsorbent for removing DMTS from water.
文摘Based on TM images,ArcGIS and landscape ecology,4 typical roads in the Pearl River Delta are taken for example to analyze infl uence range of highway,and study the laws of highway construction infl uencing landscape patterns by reviewing landscape pattern changes in areas along the highways. According to the research,for Yuebei Section(north Guangdong) of Beijing–Zhuhai Highway,road construction has signifi cant infl uence on landscape patterns of the 300-m wide buffer zone(especially woodland and urban land); for Foshan–Kaiping Highway,road construction has significant influence on landscape patterns of the 1,000-m wide buffer zone(especially woodland and agricultural land); for Dongguan–Shenzhen Highway,road construction has signifi cant infl uence on landscape patterns of the 8,000-m wide buffer zone(especially woodland and urban land).
基金supported by the China Three Gorges Group Co.LTD (No.202003080)the National Key Research and Development Project (Nos.2020YFC1908702,2021YFC_(3)200704)。
文摘Previous study found that the pre-treatment of sewage sludge with nitrite improves the biogas production during the mono/two-phase anaerobic digestion (AD) using batch biochemical methane potential tests.In this study,the effects of nitrite on hydrolysisacidification,biogas production,volatile solids destruction and microbial composition in semi-continuous two-phase AD of sewage sludge were investigated.The addition of nitrite promotes sludge organic matter solubilization (+484%) and VFAs production (+98.9%),and causes an increase in the VS degradation rate during the AD process (+8.7%).The comparison of biogas production from the acidogenic and methanogenic reactors with or without the addition of nitrite implies that the nitrite has no significant effect on the overall biogas production of two-phase sludge AD process.High-throughput sequencing analysis shows that the microbial communities of bacteria and archaea in two-phase AD reactors significantly changes after the addition of nitrite.Vulcanibacillus (bacteria) and Candidatus Methanofastidiosum (archaea) become the dominant genera in the acidogenic and methanogenic reactors with the nitrite respectively.These findings provide new insights about using nitrite to promote the organic matter degradation of sewage sludge in a semicontinuous two-phase AD system.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52071161 and 52301322)the Jiangsu Provincial Natural Science Foundation(Grant No.BK20220653).
文摘In recent years,the exploitation of offshore wind resources has been attached with greater importance.As a result,semi-submersible floating wind turbines(FWTs)have gradually become a popular research topic,with the structural strength being a research hotspot as it can ensure the safe operation of FWTs.The severe sea conditions of freak waves result in enormous wave heights,extremely fast wave speeds,and concentrated energy.Thus,it is difficult to accurately simulate these effects on the loads of floating wind turbines using the potential flow theory and other theories.In this paper,the structural strength of a floating wind turbine under the action of freak waves is analyzed based on the CFD-FEA coupled method.The effects of the mooring system and the wind load are considered in the time domain,and the CFD method is applied to analyze the wave load of the floating wind turbine under the extreme sea state of freak waves.The strength and motion of the floating wind turbine float structure are analyzed by combining the CFD method and the FEA method,and the analytical results of the mutual transfer of these two methods are taken as the initial quantities for further analysis.The accuracy of the analytical model of the CFD-FEA method is verified by the results of the tank test analysis,and the structural strength analysis under freak wave conditions is carried out for a new type of floating wind turbine.The results of this research provide useful guidance and references for the design and engineering applications of offshore floating wind turbines.
基金granted by the Shanghai Science and Technology Commission (Grant No.15DZ1205800)
文摘Chemical analysis of groundwater in petroliferous basins can be an effective way to determine the regional hydrogeological regime and to evaluate the preservation conditions of hydrocarbons. This paper presents the hydrochemical distribution of both individual aquifers and different structural units within the Palaeogene strata of the Gaoyou subbasin in the North Jiangsu Basin, east China. The results show that the salinity of the Palaeogene aquifers in the Gaoyou subbasin displays a systematic increase from the central deep depression to the periphery areas, and shows a reverse trend as the burial depth increases. Salinity maps of individual aquifers suggest that formation water in the deep layers at the centre of the study area probably retains original features of fresh lake water. Geofluids near the central deep depression of the Gaoyou subbasin migrate vertically through the Zhenwu and Hanliu faults, while those of the northern slope belt mainly flow laterally through aquifers. Both low and high salinity formation water can be found in the hydrocarbon producing areas. The low salinity zones commonly affected by infiltrated meteoric water are unfavourable conditions for the preservation of trapped hydrocarbons.
基金Supported by Key Special Item of the National Science and TechnologyWater Body Pollution Control and Treatment(2008ZX07421-001)
文摘[Objective] The research aimed to study key problems of a new environmental dredging based on ecological protection and subsequent ecological restoration. [Method] People paid more attention to sediment pollutant removal in environmental dredging, without considering coming aquatic eco-restoration work after dredging. Factor affecting aquatic ecosystem existence and growth was screened, and ecological dredging manner was put forward. [Result] On the basis of analyzing dredging objective, effect and influence, started from ecological protection and subsequent ecological restoration, water depth and substrate were screened as priority control factors of the environmental sediment dredging. New manner of combining sediment dredging to reshape underwater terrain was put forward. [Conclusion] The research provided solution for water depth and substrate demands of the subsequent ecological restoration.
