Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies...Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies.This study evaluated the feasibility of European Community Bureau of Reference(BCR)sequential extraction,Ca(NO_(3))_(2)extraction,and water extraction on assessing Cd and Pb availability in agricultural soil amended with slaked lime,magnesium hydroxide,corn stover biochar,and calcium dihydrogen phosphate.Moreover,the enriched isotope tracing technique(^(112)Cd and^(206)Pb)was employed to evaluate the aging process of newly introduced Cd and Pbwithin 56 days’incubation.Results demonstrated that extractable pools by BCR and Ca(NO_(3))_(2)extraction were little impacted by amendments and showed little correlation with soil pH.This is notable because soil pH is closely linked to metal availability,indicating these extraction methods may not adequately reflect metal availability.Conversely,water-soluble concentrations of Cd and Pb were markedly influenced by amendments and exhibited strong correlations with pH(Pearson’s r:-0.908 to-0.825,P<0.001),suggesting water extraction as a more sensitive approach.Furthermore,newly introduced metals underwent a more evident aging process as demonstrated by acid-soluble and water-soluble pools.Additionally,water-soluble concentrations of essential metals were impacted by soil amendments,raising caution on their potential effects on plant growth.These findings suggest water extraction as a promising and attractive method to evaluate Cd and Pb availability,which will help provide assessment guidance for environmental risks caused by heavy metals and develop efficient remediation strategies.展开更多
Precipitation plays a pivotal role in wet deposition,significantly affecting aerosol purification.The efficacy of precipitation in removing aerosols depends on its type and the characteristics of the particulates invo...Precipitation plays a pivotal role in wet deposition,significantly affecting aerosol purification.The efficacy of precipitation in removing aerosols depends on its type and the characteristics of the particulates involved.However,further research is necessary to fully understand how precipitation impacts PM_(2.5)components.This study utilized high-temporalresolution data on PM_(2.5),its components and meteorological factors to examine varying responses influenced by precipitation intensity and duration.The findings indicate that increased rainfall intensity and duration enhance PM_(2.5)and its constituents removal efficiency.Specifically,longer precipitation periods significantly improve PM_(2.5)purification,especially with drizzle and light rain.Moreover,there is a direct correlation between preprecipitation PM_(2.5)levels and its scavenging rates,with drizzle potentially exacerbating PM_(2.5)pollution under cleaner conditions(≤35μg/m^(3)).Seasonally,the efficacy of removing PM_(2.5)components varies notably in response to drizzle and light rain.In spring,higher PM_(2.5)levels after drizzlewere primarily due to increased organic carbon concentrations favored by higher relative humidity and lower pH conditions compared to other seasons,conducive to secondary organic aerosol production.Lower wind speeds and higher temperatures further contribute to water-soluble organic carbon accumulation.Daytime and nighttime precipitation exerted differing influences on PM_(2.5)components,particularly in spring where daytime drizzle and light rain significantly increased PM_(2.5)and its constituents,notably NO_(3)-,potentially associated with phase distribution changes between gas and aerosol phases in low-temperature,high-RH conditions compared to nighttime.These results propose a dualimpact mechanism of precipitation on PM_(2.5)and provide scientific basis for designing effective control strategies.展开更多
Background The intensive use of herbicides in agriculture raises concerns about their residual impacts on non-target crops such as cotton(Gossypium hirsutum L.),which is often rotated with cereals,sugar beet,and canol...Background The intensive use of herbicides in agriculture raises concerns about their residual impacts on non-target crops such as cotton(Gossypium hirsutum L.),which is often rotated with cereals,sugar beet,and canola.Butisanstar(BUT)and clopyralid(CLO)are widely used for broadleaf weed control in these rotations.However,how residual herbicide activity influences cotton growth and development is not well understood.This study evaluated these residual effects by measuring multiple growth parameters in a greenhouse.Cotton was grown for 40 days in soil incubated for 90 days with herbicide treatments arranged in a factorial design(type:BUT,CLO,and their combination;dose:0,1/2,1,2,and 5×recommended field dose[RFD]).Results Herbicide residues reduced cotton growth in a dose-dependent manner,with greater inhibition at higher doses.The combined BUT+CLO treatment produced the strongest negative effects,followed by CLO and then BUT alone.Compared with controls,seedling emergence declined by 12%–83%,root length by 12%–87%,plant height by 10%–84%,and chlorophyll index by 12%–80%across treatments from 1/2×RFD BUT to 5×RFD BUT+CLO.Root and shoot biomass also decreased significantly.Under the 5×RFD combined treatment,shoot N,P,and K concentrations dropped by 48%,78%,and 70%,respectively,relative to the control.Conclusions Even low levels of residual BUT and CLO impair cotton growth.To mitigate these effects,it should avoid planting cotton on recently treated soils,leave sufficient intervals between herbicide application and cotton planting,and apply soil amendments to boost microbial degradation.These measures are essential for sustaining soil health and cotton productivity.展开更多
The ice-phase microphysical characteristics of a stratiform cloud system over the Qilian Mountains in northwestern China on 15 September 2022 were analyzed via aircraft data.The stratiform cloud system developed under...The ice-phase microphysical characteristics of a stratiform cloud system over the Qilian Mountains in northwestern China on 15 September 2022 were analyzed via aircraft data.The stratiform cloud system developed under southwesterly flows at 500 hPa and was affected locally by topography.Synoptic features and aircraft observations revealed strengthened cloud development on the leeward slope.The ice particle habits and microphysical processes at heights of 6-8 km were investigated.The cloud system was characterized by extremely low supercooled liquid water content at temperatures between−4℃ and−17℃.The ice particle concentrations ranged predominantly from 10 to 30 L^(−1),corresponding to ice water content ranging from 0.01 to 0.05 g m^(−3).Active ice aggregation was observed at temperatures colder than−10°C.The windward side of the cloud system exhibited weaker development and two distinct cloud layers.Intense orographic uplift on the leeward slope enhanced ice particle aggregation.The clouds on the leeside presented lower ice particle concentrations but larger sizes than those on the windward side.The influence of aggregation on the ice particle size distribution was reflected in two main aspects.One aspect was the bimodal spectra at−16℃,with the first peak at 125μm and subpeak at 400-500μm;the other was the broadened size spectra at−13℃ due to significant aggregation of dendrites.展开更多
In this study,a strategy is proposed to use the congestion index as a new input feature.This approach can reveal more deeply the complex effects of traffic conditions on variations in particulate matter(PM_(2.5))conce...In this study,a strategy is proposed to use the congestion index as a new input feature.This approach can reveal more deeply the complex effects of traffic conditions on variations in particulate matter(PM_(2.5))concentrations.To assess the effectiveness of this strategy,we conducted an ablation experiment on the congestion index and implemented a multi-scale input model.Compared with conventional models,the strategy reduces the root mean square error(RMSE)of all benchmark models by>6.07%on average,and the bestperforming model reduces it by 12.06%,demonstrating excellent performance improvement.In addition,evenwith high traffic emissions,the RMSE during peak hours is still below 9.83μg/m^(3),which proves the effectiveness of the strategy by effectively addressing pollution hotspots.This study provides new ideas for improving urban environmental quality and public health and anticipates inspiring further research in this domain.展开更多
To provide advanced diagnostic techniques for diagnosing the outlet temperature distribution and species concentrations of future advanced combustors,this study focuses on a dual-swirl single-dome rectangular combusto...To provide advanced diagnostic techniques for diagnosing the outlet temperature distribution and species concentrations of future advanced combustors,this study focuses on a dual-swirl single-dome rectangular combustor.Through the integration of multiple diagnostics,simultaneous measurement of outlet temperature distribution and species concentrations was achieved.The study validates the engineering applicability of these simultaneous measurements using tungsten-rhenium(W-Re)thermocouples and Coherent Anti-Stokes Raman Scattering(CARS),CARS and Tunable Diode Laser Absorption Spectroscopy(TDLAS),as well as Gas Analysis(GA)and Mass Spectrometry(MS).The results demonstrate that measurements by thermocouples and CARS exhibit good consistency and repeatability,with a relative deviation of less than 4%,fully meeting the requirements of engineering experiments.The spatial distribution reconstruction results of TDLAS can reflect the temperature distribution characteristics at the combustor outlet.Temperature comparison between TDLAS and CARS at single-point positions shows consistent results,with a relative deviation of less than 11%and 7%under both conditions,respectively.Simultaneous measurements by integrating GA and MS show high engineering applicability for the first time,meeting the requirements for measuring both inorganic species and free radicals at the combustor outlet.Under C_(1)condition,the relative deviations of four key species(Unburned Hydrocarbon(UHC),NO,O_(2),and CO_(2))remain within 2%,while that of NO_(2)is slightly higher at approximately 8%.Under C_(2)condition,the overall deviations increase for most species,with only O_(2)and CO_(2)maintaining relatively low deviations.The primary species of UHCs at the combustor outlet under both conditions are small molecular hydrocarbons(C_(3)-C_(8))and RO_(2)radicals,accounting for over 90%of total UHC.Specifically,RO_(2)species(R is C_(1)-C_(2)alkyl groups)are the predominant species,accounting for 74.3%and 82.1%of total RO_(2)under both conditions,respectively.These integrated diagnostic methods for temperature and species concentrations at the combustor outlet serve as a crucial reference for its engineering applications.展开更多
Moisture-enabled electricity generation(MEG)has emerged as a promising sustainable energy harvesting technology,comparable to photovoltaics,thermoelectrics,and triboelectrics[1].MEGs generate electricity by converting...Moisture-enabled electricity generation(MEG)has emerged as a promising sustainable energy harvesting technology,comparable to photovoltaics,thermoelectrics,and triboelectrics[1].MEGs generate electricity by converting the chemical potential of moisture into electric energy through interactions with hygroscopic materials and nanostructured interfaces.Unlike solar or thermal harvesters,MEGs operate continuously by utilizing ubiquitous atmospheric moisture,granting them unique spatial and temporal adaptability.Despite nearly a decade of progress and the exploration of diverse material systems for MEG,the overall output power remains significantly limited due to inherently low charge carrier concentrations and restricted ion diffusion fluxes[2].As a result,standalone MEG devices often deliver low and unstable output,limiting practical applications.To enhance performance and versatility,recent efforts have explored hybridization of MEG with other ambient energy sources such as triboelectric or thermoelectric effects.展开更多
As one of the main characteristics of atmospheric pollutants,PM_(2.5) severely affects human health and has received widespread attention in recent years.How to predict the variations of PM_(2.5) concentrations with h...As one of the main characteristics of atmospheric pollutants,PM_(2.5) severely affects human health and has received widespread attention in recent years.How to predict the variations of PM_(2.5) concentrations with high accuracy is an important topic.The PM_(2.5) monitoring stations in Xinjiang Uygur Autonomous Region,China,are unevenly distributed,which makes it challenging to conduct comprehensive analyses and predictions.Therefore,this study primarily addresses the limitations mentioned above and the poor generalization ability of PM_(2.5) concentration prediction models across different monitoring stations.We chose the northern slope of the Tianshan Mountains as the study area and took the January−December in 2019 as the research period.On the basis of data from 21 PM_(2.5) monitoring stations as well as meteorological data(temperature,instantaneous wind speed,and pressure),we developed an improved model,namely GCN−TCN−AR(where GCN is the graph convolution network,TCN is the temporal convolutional network,and AR is the autoregression),for predicting PM_(2.5) concentrations on the northern slope of the Tianshan Mountains.The GCN−TCN−AR model is composed of an improved GCN model,a TCN model,and an AR model.The results revealed that the R2 values predicted by the GCN−TCN−AR model at the four monitoring stations(Urumqi,Wujiaqu,Shihezi,and Changji)were 0.93,0.91,0.93,and 0.92,respectively,and the RMSE(root mean square error)values were 6.85,7.52,7.01,and 7.28μg/m^(3),respectively.The performance of the GCN−TCN−AR model was also compared with the currently neural network models,including the GCN−TCN,GCN,TCN,Support Vector Regression(SVR),and AR.The GCN−TCN−AR outperformed the other current neural network models,with high prediction accuracy and good stability,making it especially suitable for the predictions of PM_(2.5)concentrations.This study revealed the significant spatiotemporal variations of PM_(2.5)concentrations.First,the PM_(2.5) concentrations exhibited clear seasonal fluctuations,with higher levels typically observed in winter and differences presented between months.Second,the spatial distribution analysis revealed that cities such as Urumqi and Wujiaqu have high PM_(2.5) concentrations,with a noticeable geographical clustering of pollutions.Understanding the variations in PM_(2.5) concentrations is highly important for the sustainable development of ecological environment in arid areas.展开更多
Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) +...Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) + (2% -4%) CO(2)) and in air (control) at 1 degreesC to investigate the effects of different O(2) and CO(2) concentrations on physiological properties, quality and storability of the fruits during storage. The results indicated that compared with other treatments, CA with high O(2) concentration decreased fruit decay and ethanol content, but increased the accumulation of malondialdehyde (MDA) and stimulated browning. CA with high CO(2) concentration inhibited polyphenol oxidase (PPO) activity, reduced MDA content, maintained vitamin C content and firmness, decreased fruit decay and browning. Soluble solids contents (SSC) were not significantly affected by different atmosphere treatments. 'Napoleon' fruits stored in 5% O(2) + 10% CO(2) for as long as 80 d were of good quality, but only 40, 20 and 30 d stored in MAP, 70% O(2) + 0% CO(2) and air, re-spectively.展开更多
The bark of Pteroce/tis tatarinowii is a raw material for manufacturing XuanPaper. The effects of Ca^(2+) concentrations on the accumulation of mineral elements in the bark,leaf and root of Pteroceltis tatarinowii wer...The bark of Pteroce/tis tatarinowii is a raw material for manufacturing XuanPaper. The effects of Ca^(2+) concentrations on the accumulation of mineral elements in the bark,leaf and root of Pteroceltis tatarinowii were studied under controlled conditions. The types ofHoagland nutrient solution with three Ca^(2+) concentrations levels (200, 400 and 600 μg·g^(-1))and a control (without Ca^(2+)) were designed to culture Pteroceltis tatarinowii. After 6 months,contents of seven mineral elements including Ca, K, Mg, Mn, Zn, Cu and Na in the root, leaf and barkwere analyzed. The results indicated that Ca accumulations content in the root, leaf and bark hadpositively relation with Ca^(2+) concentrations (200, 400, 600 μg · g^(-1)), and the order of theCa content in the three components was root>leaf>bark. Ca content in the root treated with 600 μg·g^(-1) Ca^(2+) concentrations was 5.5 times as high as that of the control, and about 1.4 times ashigh as that of the root treated in 200 and 400 μg/g Ca^(2+) concentrations respectively. On thecontrary, K and Mg contents in the root, leaf and bark were negatively related to Ca^(2+)concentrations, especially in the bark, and their accumulation trend followed the order ofleaf>root>bark. K content in the bark treated with 600 μg ·g^(-1) Ca^(2+) concentrations was 39.3%of that of the control, and was 79.0% and 91.8% of that of the bark treated with 200 μg ·g^(-1)and 400 μg ·g^(-1) Ca^(2+) concentrations respectively; Mg content in the bark treated with 600μg ·g^(-1) Ca^(2+) concentrations was 23.4% of that of the control, and was 27.1% and 35.4% ofthat of the bark treated with 200 and 400 μg·g^(-1) Ca^(2+) concentrations respectively. Comparedwith the control, the general tendency of Mn, Zn and Cu content decreased with increasing of Ca^(2+)concentrations and their contents were in the order: root>leaf>bark. Based on the results of thisstudy, the experiment has been useful for providing academic bases in improving the bark quality ofPteroceltis tatarinowii on non-limestone soil.展开更多
In order to assess the mercury Hg pollution in urban stormwater runoff in Nanjing 11 rainfall events in the Maqun region of Nanjing circle expressway were monitored and the events mean concentrations EMC of Hg and the...In order to assess the mercury Hg pollution in urban stormwater runoff in Nanjing 11 rainfall events in the Maqun region of Nanjing circle expressway were monitored and the events mean concentrations EMC of Hg and the impact of rainfall characteristics on Hg pollution in runoff were analyzed.Results show that the pollution of different Hg species is serious and total Hg THg dissolved Hg HgD and particulate Hg HgP are found to be in the range of 0.173 to 3.347 0.069 to 0.862 and 0.104 to 2.485μg/L respectively.The average EMC value of THg exceeds the Ⅴ class limitation value of Quality standards of surface water environment GB 3838-2002 of China. Hg in runoff mainly exists in particulate form and the concentrations of Hgre 0.250 to 2.821 μg/L are far more than those of Hg0 0.023 to 0.215 μg/L and Hg2＋ 0.026 to 0.359 μg/L . The order of rainfall characteristics impacting on Hg pollution in runoff is dry periods 〉runoff time〉duration of rainfall〉storm intensity〉rainfall.展开更多
The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and photochemical smog episodes in Shanghai in 2009. The number of haze days acco...The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and photochemical smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe （visibility 〈 2 km） and moderate （2 km 〈 visibility 〈 3 km） haze, mainly distributed in winter and spring. The mean particle number concentration was about 17,000/cm3 in haze, more than 2 times that in clean days. The greatest increase of particle number concentration was in 0.5-1μm and 1-10 μm size fractions during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50-100 nm and 100-200 nm fractions during photochemical smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, photochemical smog and clean days were 102, 49, 15 μm3/cm3 and 949, 649, 206 μm2/cm3, respectively. As haze events got more severe, the number concentration of particles smaller than 50 nm decreased, but the particles of 50-200 nm and 0.5-1μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH4, SO24- and NO3 increased great/y, followed by Na＋, IC, Ca2＋ and CI-. These ions were very different in size-resolved particles during haze and photochemical smog episodes.展开更多
Two new freshwater atyid shrimps, Caridina angustipes sp nov.and C clavipes sp nov.from Hunan Province,China are described. C angustipes sp nov.is similar to C baojingensis Guo,He et Bai,1992,b...Two new freshwater atyid shrimps, Caridina angustipes sp nov.and C clavipes sp nov.from Hunan Province,China are described. C angustipes sp nov.is similar to C baojingensis Guo,He et Bai,1992,but with longer rostrum,15-27 dorsal teeth,3-6 ventral teeth,and straighter inner margin of endopods in male 1st pleopods. C clavipes sp nov.is similar to C angustipes ,but with narrower distal and fewer spines on inner margin of endopds in male 1st pleopods,and shorter and thinner appendix masculina in male 2nd pleopods with only 1 spine on inner lateral margin and 4 spines in apex.The holotypes are deposited in Shanghai Fisheries University.Some representative paratypes are deposited in Foshan Science and Technology College.展开更多
The bark of Pteroceltis tatarinowii is a raw material for manufacturing Xuan Paper. The effects of Ca2+ concentrations on the accumulation of mineral elements in the bark, leaf and root of Pteroceltis tatarinowii were...The bark of Pteroceltis tatarinowii is a raw material for manufacturing Xuan Paper. The effects of Ca2+ concentrations on the accumulation of mineral elements in the bark, leaf and root of Pteroceltis tatarinowii were studied under controlled condi-tions. The types of Hoagland nutrient solution with three Ca2+ concentrations levels (200, 400 and 600 靏g-1) and a control (without Ca2+) were designed to culture Pteroceltis tatarinowii. After 6 months, contents of seven mineral elements including Ca, K, Mg, Mn, Zn, Cu and Na in the root, leaf and bark were analyzed. The results indicated that Ca accumulations content in the root, leaf and bark had positively relation with Ca2+ concentrations (200, 400, 600 靏g-1), and the order of the Ca content in the three components was root】leaf】bark. Ca content in the root treated with 600 靏g-1 Ca2+ concentrations was 5.5 times as high as that of the control, and about 1.4 times as high as that of the root treated in 200 and 400 靏/g Ca2+ concentrations respectively. On the contrary, K and Mg contents in the root, leaf and bark were negatively related to Ca2+ concentrations, especially in the bark, and their accumulation trend followed the order of leaf】root】bark. K content in the bark treated with 600 靏g-1 Ca2+ con-centrations was 39.3% of that of the control, and was 79.0% and 91.8% of that of the bark treated with 200 靏g-1 and 400靏g-1 Ca2+ concentrations respectively; Mg content in the bark treated with 600 靏g-1 Ca2+ concentrations was 23.4% of that of the control, and was 27.1% and 35.4% of that of the bark treated with 200 and 400 靏g-1 Ca2+ concentrations respectively. Com-pared with the control, the general tendency of Mn, Zn and Cu content decreased with increasing of Ca2+ concentrations and their contents were in the order: root】leaf】bark. Based on the results of this study, the experiment has been useful for providing academic bases in improving the bark quality of Pteroceltis tatarinowii on non-limestone soil.展开更多
Organochlorine pesticides （OCPs）, polychlorinated biphenyls （PCBs）, and polycyclic aromatic hydrocarbons （PAHs） were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflow...Organochlorine pesticides （OCPs）, polychlorinated biphenyls （PCBs）, and polycyclic aromatic hydrocarbons （PAHs） were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflowing river （Fuhe River） in North China. Total concentrations of OCPs, PCBs and PAHs in sediments ranged from 5.4 to 707.6 ng]g, 2.3 to 197.8 ng/g, and 101.3 to 6360.5 ng]g, respectively. The levels of contaminants in Fuhe River were significantly higher than those in Baiyandian Lake. For hexachlorocyclohexane （HCHs） and dichlorodiphenytrich/oroethanes （DDTs）, α-HCH and p,p＇-DDT were predominant isomers; while for PCBs, PCB 28/31, PCB 40/103, PCB 60, PCB 101, and PCB 118 were predominant congeners. Possible sources derived from historical usage for OCPs and incomplete combustion fuel, wood, and coal and exhaustion of boats or cars for PAHs. Risk assessment of sediment indicated that sediments in Fuhe River were likely to pose potential biological adverse impact.展开更多
Suspended and waterborne polyurethane immobilized nitrifying bacteria have been adopted for evaluating the effects of environmental changes, such as temperature, dissolved oxygen （DO） concentration and pH, on nitrif...Suspended and waterborne polyurethane immobilized nitrifying bacteria have been adopted for evaluating the effects of environmental changes, such as temperature, dissolved oxygen （DO） concentration and pH, on nitrification characteristics under conditions of low ammonia concentrations. The results showed that nitrification was prone to complete with increasing pH, DO and temperature. Sensitivity analysis demonstrated the effects of temperature and pH on nitrification feature of suspended bacteria were slightly greater than those of immobilized nitrifying bacteria. Immobilized cells could achieve complete nitrification at low ammonia concentrations when DO was sufficient. Continuous experiments were carried out to discuss the removal of ammonia nitrogen from synthetic micropollute source water with the ammonia concentration of about 1mg/L using immobilized nitrifying bacteria pellets in an up-flow inner circulation reactor under different hydraulic retention times （HRT）. The continuous removal rate remains above 80% even under HRT 30 min. The results verified that the waterborne polyurethane immobilized nitrifying bacteria pellets had great potential applications for micro-pollution source water treatment.展开更多
In this paper, the online weather research and forecasting and chemistry （WRF-Chem） model is used to explore the impacts of urban expansion on regional weather conditions and its implication on surface ozone concent...In this paper, the online weather research and forecasting and chemistry （WRF-Chem） model is used to explore the impacts of urban expansion on regional weather conditions and its implication on surface ozone concentrations over the Pearl River Delta（PRD） and Yangtze River Delta（YRD） regions. Two scenarios of urban maps are used in the WRF-Chem to represent the early 1990s （pre-urbanization） and the current urban distribution in the PRD and the YRD. Month-long simulation results using the above land-use scenarios for March 2001 show that urbanization increases both the day- and night-time 2-m temperatures by about 0.6℃and 1.4℃, respectively. Daytime reduction in the wind speed by about 3.0 m s-1 is larger than that for the nighttime （0.5 to 2 m s-1）. The daytime increase in the PBL height （〉 200 m） is also larger than the nighttime （50-100 m）. The meteorological conditions modified by urbanization lead to detectable ozone-concentration changes in the PRD and the YRD. Urbanization increases the nighttime surface-ozone concentrations by about 4.7%-8.5% and by about 2.9%-4.2% for the daytime. In addition to modifying individual meteorological variables, urbanization also enhances the convergence zones, especially in the PRD. More importantly, urbanization has different effects on the surface ozone for the PRD and the YRD, presumably due to their urbanization characteristics and geographical locations. Even though the PRD has a smaller increase in the surface temperature than the YRD, it has （a） weaker surface wind speed, （b） smaller increase in PBL heights, and （c） stronger convergence zones. The latter three factors outweighed the temperature increase and resulted in a larger ozone enhancement in the PRD than the YRD.展开更多
Placer diamond mining in the Anabar area involves various operations that cause long-term (nearly a quarter of a century) environmental impacts. The long history of mining activities, the technology used to mine the p...Placer diamond mining in the Anabar area involves various operations that cause long-term (nearly a quarter of a century) environmental impacts. The long history of mining activities, the technology used to mine the placers, as well as the poor assimilative capacity of the natural systems can result in serious environmental impacts in the area. The primary geochemical processes in the diamond-bearing area are affected by the occurrence of permafrost and relict ice, the lengthy duration of ice cover in water bodies, and the widespread development of cryogenic processes. This promotes physical migration of contaminants, cryogenic metamorphization of waters, and long-term accumulation of organic contaminants in low-temperature, reduction and sedimentation barriers. In this paper, some environmental and geochemical effects of diamond mining in the Arctic area are discussed.展开更多
In 1999 aerosol samples were collected by cascade at Meteorological Tower in Beijing. The 12 group aerosol samples obtained were analyzed using PIXE method, which resulted in 20 elemental concentrations and size dist...In 1999 aerosol samples were collected by cascade at Meteorological Tower in Beijing. The 12 group aerosol samples obtained were analyzed using PIXE method, which resulted in 20 elemental concentrations and size distribution of elemental concentrations. From the observation, the elemental concentrations, size distribution of elemental concentrations and their variations are analyzed. It shows that concentrations of the most elements in aerosols increase greatly compared with those in the past except that the concentrations of V, K, Sr, and the source of aerosols has changed greatly in the past decade. Fine mode aerosols increase more rapidly in the past decade, which may be due to the contribution of coal combustion and automobile exhaust. Pb content in aerosol is much higher than that at the beginning of 1980s, and has a decreasing trend in recent years because of using non leaded gasoline.展开更多
Antibacterial ceramic was prepared by doping enamel slurry with composite phosphate inorganic antibacterial materials containing rare earth (inorganic antibacterial additives), and then the mechanisms for activating w...Antibacterial ceramic was prepared by doping enamel slurry with composite phosphate inorganic antibacterial materials containing rare earth (inorganic antibacterial additives), and then the mechanisms for activating water and improving seed germinative property were tested by nuclear magnetic resonance (NMR) and the method of testing oxygen dissolved in activated water. Results show that the half peak width of (()^(17)O-NMR) for tap water activated by the antibacterial ceramic drops from 115.36 to 99.15 Hz, and oxygen concentrations of activated water increase by 20%, germinate rate of horsebean and earthnut seeds increases by 12.5% and 7.5%, respectively. Therefore antibacterial ceramic doped enamel slurry with inorganic antibacterial additives containing rare earth can reduce the volume of clusters of water molecules, improve activation of tap water, and promote plant seeds germinate.展开更多
基金supported by the National Natural Science Foundation of Shandong(No.ZR2020ZD20)the National Natural Science Foundation of China(No.22193051)+1 种基金the National Young Top-Notch Talents(No.W03070030)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y202011).
文摘Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies.This study evaluated the feasibility of European Community Bureau of Reference(BCR)sequential extraction,Ca(NO_(3))_(2)extraction,and water extraction on assessing Cd and Pb availability in agricultural soil amended with slaked lime,magnesium hydroxide,corn stover biochar,and calcium dihydrogen phosphate.Moreover,the enriched isotope tracing technique(^(112)Cd and^(206)Pb)was employed to evaluate the aging process of newly introduced Cd and Pbwithin 56 days’incubation.Results demonstrated that extractable pools by BCR and Ca(NO_(3))_(2)extraction were little impacted by amendments and showed little correlation with soil pH.This is notable because soil pH is closely linked to metal availability,indicating these extraction methods may not adequately reflect metal availability.Conversely,water-soluble concentrations of Cd and Pb were markedly influenced by amendments and exhibited strong correlations with pH(Pearson’s r:-0.908 to-0.825,P<0.001),suggesting water extraction as a more sensitive approach.Furthermore,newly introduced metals underwent a more evident aging process as demonstrated by acid-soluble and water-soluble pools.Additionally,water-soluble concentrations of essential metals were impacted by soil amendments,raising caution on their potential effects on plant growth.These findings suggest water extraction as a promising and attractive method to evaluate Cd and Pb availability,which will help provide assessment guidance for environmental risks caused by heavy metals and develop efficient remediation strategies.
基金supported by the National Natural Science Foundation of China(No.42175124)the Science and Technology Department of Sichuan Province(No.23YFS0383)the Fundamental Research Funds for the Central Universities,China(No.2023CDSN-18).
文摘Precipitation plays a pivotal role in wet deposition,significantly affecting aerosol purification.The efficacy of precipitation in removing aerosols depends on its type and the characteristics of the particulates involved.However,further research is necessary to fully understand how precipitation impacts PM_(2.5)components.This study utilized high-temporalresolution data on PM_(2.5),its components and meteorological factors to examine varying responses influenced by precipitation intensity and duration.The findings indicate that increased rainfall intensity and duration enhance PM_(2.5)and its constituents removal efficiency.Specifically,longer precipitation periods significantly improve PM_(2.5)purification,especially with drizzle and light rain.Moreover,there is a direct correlation between preprecipitation PM_(2.5)levels and its scavenging rates,with drizzle potentially exacerbating PM_(2.5)pollution under cleaner conditions(≤35μg/m^(3)).Seasonally,the efficacy of removing PM_(2.5)components varies notably in response to drizzle and light rain.In spring,higher PM_(2.5)levels after drizzlewere primarily due to increased organic carbon concentrations favored by higher relative humidity and lower pH conditions compared to other seasons,conducive to secondary organic aerosol production.Lower wind speeds and higher temperatures further contribute to water-soluble organic carbon accumulation.Daytime and nighttime precipitation exerted differing influences on PM_(2.5)components,particularly in spring where daytime drizzle and light rain significantly increased PM_(2.5)and its constituents,notably NO_(3)-,potentially associated with phase distribution changes between gas and aerosol phases in low-temperature,high-RH conditions compared to nighttime.These results propose a dualimpact mechanism of precipitation on PM_(2.5)and provide scientific basis for designing effective control strategies.
文摘Background The intensive use of herbicides in agriculture raises concerns about their residual impacts on non-target crops such as cotton(Gossypium hirsutum L.),which is often rotated with cereals,sugar beet,and canola.Butisanstar(BUT)and clopyralid(CLO)are widely used for broadleaf weed control in these rotations.However,how residual herbicide activity influences cotton growth and development is not well understood.This study evaluated these residual effects by measuring multiple growth parameters in a greenhouse.Cotton was grown for 40 days in soil incubated for 90 days with herbicide treatments arranged in a factorial design(type:BUT,CLO,and their combination;dose:0,1/2,1,2,and 5×recommended field dose[RFD]).Results Herbicide residues reduced cotton growth in a dose-dependent manner,with greater inhibition at higher doses.The combined BUT+CLO treatment produced the strongest negative effects,followed by CLO and then BUT alone.Compared with controls,seedling emergence declined by 12%–83%,root length by 12%–87%,plant height by 10%–84%,and chlorophyll index by 12%–80%across treatments from 1/2×RFD BUT to 5×RFD BUT+CLO.Root and shoot biomass also decreased significantly.Under the 5×RFD combined treatment,shoot N,P,and K concentrations dropped by 48%,78%,and 70%,respectively,relative to the control.Conclusions Even low levels of residual BUT and CLO impair cotton growth.To mitigate these effects,it should avoid planting cotton on recently treated soils,leave sufficient intervals between herbicide application and cotton planting,and apply soil amendments to boost microbial degradation.These measures are essential for sustaining soil health and cotton productivity.
基金supported by the National Natural Science Foundation of China(Grant Nos.42475100 and 42405091)supported by the CMA Key Innovation Team(Grant No.CMA2022ZD10)+1 种基金the CMA Weather Modification Centre Innovation Team(Grant No.WMC2023IT02)the National Key R&D Program of China(Grant No.2019YFC1510305).
文摘The ice-phase microphysical characteristics of a stratiform cloud system over the Qilian Mountains in northwestern China on 15 September 2022 were analyzed via aircraft data.The stratiform cloud system developed under southwesterly flows at 500 hPa and was affected locally by topography.Synoptic features and aircraft observations revealed strengthened cloud development on the leeward slope.The ice particle habits and microphysical processes at heights of 6-8 km were investigated.The cloud system was characterized by extremely low supercooled liquid water content at temperatures between−4℃ and−17℃.The ice particle concentrations ranged predominantly from 10 to 30 L^(−1),corresponding to ice water content ranging from 0.01 to 0.05 g m^(−3).Active ice aggregation was observed at temperatures colder than−10°C.The windward side of the cloud system exhibited weaker development and two distinct cloud layers.Intense orographic uplift on the leeward slope enhanced ice particle aggregation.The clouds on the leeside presented lower ice particle concentrations but larger sizes than those on the windward side.The influence of aggregation on the ice particle size distribution was reflected in two main aspects.One aspect was the bimodal spectra at−16℃,with the first peak at 125μm and subpeak at 400-500μm;the other was the broadened size spectra at−13℃ due to significant aggregation of dendrites.
基金supported by the Enterprises Research Project(Nos.W2021JSKF0922 and W2023JSKF0116)the Key industrialization Projects of Intelligent Manufacturing Institute,Hefei University of Technology(No.IMICZ2019001).
文摘In this study,a strategy is proposed to use the congestion index as a new input feature.This approach can reveal more deeply the complex effects of traffic conditions on variations in particulate matter(PM_(2.5))concentrations.To assess the effectiveness of this strategy,we conducted an ablation experiment on the congestion index and implemented a multi-scale input model.Compared with conventional models,the strategy reduces the root mean square error(RMSE)of all benchmark models by>6.07%on average,and the bestperforming model reduces it by 12.06%,demonstrating excellent performance improvement.In addition,evenwith high traffic emissions,the RMSE during peak hours is still below 9.83μg/m^(3),which proves the effectiveness of the strategy by effectively addressing pollution hotspots.This study provides new ideas for improving urban environmental quality and public health and anticipates inspiring further research in this domain.
基金support of the National Major Science and Technology Projects of China(No.J2019-V-0005-0096)the National Key Research and Development Program of China(No.2020YFA0405700).
文摘To provide advanced diagnostic techniques for diagnosing the outlet temperature distribution and species concentrations of future advanced combustors,this study focuses on a dual-swirl single-dome rectangular combustor.Through the integration of multiple diagnostics,simultaneous measurement of outlet temperature distribution and species concentrations was achieved.The study validates the engineering applicability of these simultaneous measurements using tungsten-rhenium(W-Re)thermocouples and Coherent Anti-Stokes Raman Scattering(CARS),CARS and Tunable Diode Laser Absorption Spectroscopy(TDLAS),as well as Gas Analysis(GA)and Mass Spectrometry(MS).The results demonstrate that measurements by thermocouples and CARS exhibit good consistency and repeatability,with a relative deviation of less than 4%,fully meeting the requirements of engineering experiments.The spatial distribution reconstruction results of TDLAS can reflect the temperature distribution characteristics at the combustor outlet.Temperature comparison between TDLAS and CARS at single-point positions shows consistent results,with a relative deviation of less than 11%and 7%under both conditions,respectively.Simultaneous measurements by integrating GA and MS show high engineering applicability for the first time,meeting the requirements for measuring both inorganic species and free radicals at the combustor outlet.Under C_(1)condition,the relative deviations of four key species(Unburned Hydrocarbon(UHC),NO,O_(2),and CO_(2))remain within 2%,while that of NO_(2)is slightly higher at approximately 8%.Under C_(2)condition,the overall deviations increase for most species,with only O_(2)and CO_(2)maintaining relatively low deviations.The primary species of UHCs at the combustor outlet under both conditions are small molecular hydrocarbons(C_(3)-C_(8))and RO_(2)radicals,accounting for over 90%of total UHC.Specifically,RO_(2)species(R is C_(1)-C_(2)alkyl groups)are the predominant species,accounting for 74.3%and 82.1%of total RO_(2)under both conditions,respectively.These integrated diagnostic methods for temperature and species concentrations at the combustor outlet serve as a crucial reference for its engineering applications.
基金the financial support of the National Natural Science Foundation of China(No.22205165).
文摘Moisture-enabled electricity generation(MEG)has emerged as a promising sustainable energy harvesting technology,comparable to photovoltaics,thermoelectrics,and triboelectrics[1].MEGs generate electricity by converting the chemical potential of moisture into electric energy through interactions with hygroscopic materials and nanostructured interfaces.Unlike solar or thermal harvesters,MEGs operate continuously by utilizing ubiquitous atmospheric moisture,granting them unique spatial and temporal adaptability.Despite nearly a decade of progress and the exploration of diverse material systems for MEG,the overall output power remains significantly limited due to inherently low charge carrier concentrations and restricted ion diffusion fluxes[2].As a result,standalone MEG devices often deliver low and unstable output,limiting practical applications.To enhance performance and versatility,recent efforts have explored hybridization of MEG with other ambient energy sources such as triboelectric or thermoelectric effects.
基金supported by the Program of Support Xinjiang by Technology(2024E02028,B2-2024-0359)Xinjiang Tianchi Talent Program of 2024,the Foundation of Chinese Academy of Sciences(B2-2023-0239)the Youth Foundation of Shandong Natural Science(ZR2023QD070).
文摘As one of the main characteristics of atmospheric pollutants,PM_(2.5) severely affects human health and has received widespread attention in recent years.How to predict the variations of PM_(2.5) concentrations with high accuracy is an important topic.The PM_(2.5) monitoring stations in Xinjiang Uygur Autonomous Region,China,are unevenly distributed,which makes it challenging to conduct comprehensive analyses and predictions.Therefore,this study primarily addresses the limitations mentioned above and the poor generalization ability of PM_(2.5) concentration prediction models across different monitoring stations.We chose the northern slope of the Tianshan Mountains as the study area and took the January−December in 2019 as the research period.On the basis of data from 21 PM_(2.5) monitoring stations as well as meteorological data(temperature,instantaneous wind speed,and pressure),we developed an improved model,namely GCN−TCN−AR(where GCN is the graph convolution network,TCN is the temporal convolutional network,and AR is the autoregression),for predicting PM_(2.5) concentrations on the northern slope of the Tianshan Mountains.The GCN−TCN−AR model is composed of an improved GCN model,a TCN model,and an AR model.The results revealed that the R2 values predicted by the GCN−TCN−AR model at the four monitoring stations(Urumqi,Wujiaqu,Shihezi,and Changji)were 0.93,0.91,0.93,and 0.92,respectively,and the RMSE(root mean square error)values were 6.85,7.52,7.01,and 7.28μg/m^(3),respectively.The performance of the GCN−TCN−AR model was also compared with the currently neural network models,including the GCN−TCN,GCN,TCN,Support Vector Regression(SVR),and AR.The GCN−TCN−AR outperformed the other current neural network models,with high prediction accuracy and good stability,making it especially suitable for the predictions of PM_(2.5)concentrations.This study revealed the significant spatiotemporal variations of PM_(2.5)concentrations.First,the PM_(2.5) concentrations exhibited clear seasonal fluctuations,with higher levels typically observed in winter and differences presented between months.Second,the spatial distribution analysis revealed that cities such as Urumqi and Wujiaqu have high PM_(2.5) concentrations,with a noticeable geographical clustering of pollutions.Understanding the variations in PM_(2.5) concentrations is highly important for the sustainable development of ecological environment in arid areas.
文摘Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) + (2% -4%) CO(2)) and in air (control) at 1 degreesC to investigate the effects of different O(2) and CO(2) concentrations on physiological properties, quality and storability of the fruits during storage. The results indicated that compared with other treatments, CA with high O(2) concentration decreased fruit decay and ethanol content, but increased the accumulation of malondialdehyde (MDA) and stimulated browning. CA with high CO(2) concentration inhibited polyphenol oxidase (PPO) activity, reduced MDA content, maintained vitamin C content and firmness, decreased fruit decay and browning. Soluble solids contents (SSC) were not significantly affected by different atmosphere treatments. 'Napoleon' fruits stored in 5% O(2) + 10% CO(2) for as long as 80 d were of good quality, but only 40, 20 and 30 d stored in MAP, 70% O(2) + 0% CO(2) and air, re-spectively.
基金This paper is supported by National Natural Science Foundation of China (No. 39970608).
文摘The bark of Pteroce/tis tatarinowii is a raw material for manufacturing XuanPaper. The effects of Ca^(2+) concentrations on the accumulation of mineral elements in the bark,leaf and root of Pteroceltis tatarinowii were studied under controlled conditions. The types ofHoagland nutrient solution with three Ca^(2+) concentrations levels (200, 400 and 600 μg·g^(-1))and a control (without Ca^(2+)) were designed to culture Pteroceltis tatarinowii. After 6 months,contents of seven mineral elements including Ca, K, Mg, Mn, Zn, Cu and Na in the root, leaf and barkwere analyzed. The results indicated that Ca accumulations content in the root, leaf and bark hadpositively relation with Ca^(2+) concentrations (200, 400, 600 μg · g^(-1)), and the order of theCa content in the three components was root>leaf>bark. Ca content in the root treated with 600 μg·g^(-1) Ca^(2+) concentrations was 5.5 times as high as that of the control, and about 1.4 times ashigh as that of the root treated in 200 and 400 μg/g Ca^(2+) concentrations respectively. On thecontrary, K and Mg contents in the root, leaf and bark were negatively related to Ca^(2+)concentrations, especially in the bark, and their accumulation trend followed the order ofleaf>root>bark. K content in the bark treated with 600 μg ·g^(-1) Ca^(2+) concentrations was 39.3%of that of the control, and was 79.0% and 91.8% of that of the bark treated with 200 μg ·g^(-1)and 400 μg ·g^(-1) Ca^(2+) concentrations respectively; Mg content in the bark treated with 600μg ·g^(-1) Ca^(2+) concentrations was 23.4% of that of the control, and was 27.1% and 35.4% ofthat of the bark treated with 200 and 400 μg·g^(-1) Ca^(2+) concentrations respectively. Comparedwith the control, the general tendency of Mn, Zn and Cu content decreased with increasing of Ca^(2+)concentrations and their contents were in the order: root>leaf>bark. Based on the results of thisstudy, the experiment has been useful for providing academic bases in improving the bark quality ofPteroceltis tatarinowii on non-limestone soil.
基金The Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘In order to assess the mercury Hg pollution in urban stormwater runoff in Nanjing 11 rainfall events in the Maqun region of Nanjing circle expressway were monitored and the events mean concentrations EMC of Hg and the impact of rainfall characteristics on Hg pollution in runoff were analyzed.Results show that the pollution of different Hg species is serious and total Hg THg dissolved Hg HgD and particulate Hg HgP are found to be in the range of 0.173 to 3.347 0.069 to 0.862 and 0.104 to 2.485μg/L respectively.The average EMC value of THg exceeds the Ⅴ class limitation value of Quality standards of surface water environment GB 3838-2002 of China. Hg in runoff mainly exists in particulate form and the concentrations of Hgre 0.250 to 2.821 μg/L are far more than those of Hg0 0.023 to 0.215 μg/L and Hg2＋ 0.026 to 0.359 μg/L . The order of rainfall characteristics impacting on Hg pollution in runoff is dry periods 〉runoff time〉duration of rainfall〉storm intensity〉rainfall.
基金supported by the National Natural Science Foundation of China (Nos.21190053, 21177025)the Shanghai Science and Technology Commission of Shanghai Municipality (Nos.13XD1400700, 12DJ1400100)+1 种基金the Priority fields for Ph.D.Programs Foundation of the Ministry of Education of China (No.20110071130003)the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB05010200)
文摘The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and photochemical smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe （visibility 〈 2 km） and moderate （2 km 〈 visibility 〈 3 km） haze, mainly distributed in winter and spring. The mean particle number concentration was about 17,000/cm3 in haze, more than 2 times that in clean days. The greatest increase of particle number concentration was in 0.5-1μm and 1-10 μm size fractions during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50-100 nm and 100-200 nm fractions during photochemical smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, photochemical smog and clean days were 102, 49, 15 μm3/cm3 and 949, 649, 206 μm2/cm3, respectively. As haze events got more severe, the number concentration of particles smaller than 50 nm decreased, but the particles of 50-200 nm and 0.5-1μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH4, SO24- and NO3 increased great/y, followed by Na＋, IC, Ca2＋ and CI-. These ions were very different in size-resolved particles during haze and photochemical smog episodes.
文摘Two new freshwater atyid shrimps, Caridina angustipes sp nov.and C clavipes sp nov.from Hunan Province,China are described. C angustipes sp nov.is similar to C baojingensis Guo,He et Bai,1992,but with longer rostrum,15-27 dorsal teeth,3-6 ventral teeth,and straighter inner margin of endopods in male 1st pleopods. C clavipes sp nov.is similar to C angustipes ,but with narrower distal and fewer spines on inner margin of endopds in male 1st pleopods,and shorter and thinner appendix masculina in male 2nd pleopods with only 1 spine on inner lateral margin and 4 spines in apex.The holotypes are deposited in Shanghai Fisheries University.Some representative paratypes are deposited in Foshan Science and Technology College.
基金This paper is supported by National Natural Science Foundation of China (No. 39970608).
文摘The bark of Pteroceltis tatarinowii is a raw material for manufacturing Xuan Paper. The effects of Ca2+ concentrations on the accumulation of mineral elements in the bark, leaf and root of Pteroceltis tatarinowii were studied under controlled condi-tions. The types of Hoagland nutrient solution with three Ca2+ concentrations levels (200, 400 and 600 靏g-1) and a control (without Ca2+) were designed to culture Pteroceltis tatarinowii. After 6 months, contents of seven mineral elements including Ca, K, Mg, Mn, Zn, Cu and Na in the root, leaf and bark were analyzed. The results indicated that Ca accumulations content in the root, leaf and bark had positively relation with Ca2+ concentrations (200, 400, 600 靏g-1), and the order of the Ca content in the three components was root】leaf】bark. Ca content in the root treated with 600 靏g-1 Ca2+ concentrations was 5.5 times as high as that of the control, and about 1.4 times as high as that of the root treated in 200 and 400 靏/g Ca2+ concentrations respectively. On the contrary, K and Mg contents in the root, leaf and bark were negatively related to Ca2+ concentrations, especially in the bark, and their accumulation trend followed the order of leaf】root】bark. K content in the bark treated with 600 靏g-1 Ca2+ con-centrations was 39.3% of that of the control, and was 79.0% and 91.8% of that of the bark treated with 200 靏g-1 and 400靏g-1 Ca2+ concentrations respectively; Mg content in the bark treated with 600 靏g-1 Ca2+ concentrations was 23.4% of that of the control, and was 27.1% and 35.4% of that of the bark treated with 200 and 400 靏g-1 Ca2+ concentrations respectively. Com-pared with the control, the general tendency of Mn, Zn and Cu content decreased with increasing of Ca2+ concentrations and their contents were in the order: root】leaf】bark. Based on the results of this study, the experiment has been useful for providing academic bases in improving the bark quality of Pteroceltis tatarinowii on non-limestone soil.
基金supported by the National Basic Research Program (973) of China (No.2006CB403306)the National Natural Science Foundation of China (No.30870311)
文摘Organochlorine pesticides （OCPs）, polychlorinated biphenyls （PCBs）, and polycyclic aromatic hydrocarbons （PAHs） were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflowing river （Fuhe River） in North China. Total concentrations of OCPs, PCBs and PAHs in sediments ranged from 5.4 to 707.6 ng]g, 2.3 to 197.8 ng/g, and 101.3 to 6360.5 ng]g, respectively. The levels of contaminants in Fuhe River were significantly higher than those in Baiyandian Lake. For hexachlorocyclohexane （HCHs） and dichlorodiphenytrich/oroethanes （DDTs）, α-HCH and p,p＇-DDT were predominant isomers; while for PCBs, PCB 28/31, PCB 40/103, PCB 60, PCB 101, and PCB 118 were predominant congeners. Possible sources derived from historical usage for OCPs and incomplete combustion fuel, wood, and coal and exhaustion of boats or cars for PAHs. Risk assessment of sediment indicated that sediments in Fuhe River were likely to pose potential biological adverse impact.
文摘Suspended and waterborne polyurethane immobilized nitrifying bacteria have been adopted for evaluating the effects of environmental changes, such as temperature, dissolved oxygen （DO） concentration and pH, on nitrification characteristics under conditions of low ammonia concentrations. The results showed that nitrification was prone to complete with increasing pH, DO and temperature. Sensitivity analysis demonstrated the effects of temperature and pH on nitrification feature of suspended bacteria were slightly greater than those of immobilized nitrifying bacteria. Immobilized cells could achieve complete nitrification at low ammonia concentrations when DO was sufficient. Continuous experiments were carried out to discuss the removal of ammonia nitrogen from synthetic micropollute source water with the ammonia concentration of about 1mg/L using immobilized nitrifying bacteria pellets in an up-flow inner circulation reactor under different hydraulic retention times （HRT）. The continuous removal rate remains above 80% even under HRT 30 min. The results verified that the waterborne polyurethane immobilized nitrifying bacteria pellets had great potential applications for micro-pollution source water treatment.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40875076, U0833001, and40645024)the National Center for Atmospheric Research (NCAR) FY07 Director Opportunity Fund+2 种基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (IAP 07306)the Institute of Atmospheric Physics, the Chinese Academy of Sciences(LAPC-KF-2006-12)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry of China
文摘In this paper, the online weather research and forecasting and chemistry （WRF-Chem） model is used to explore the impacts of urban expansion on regional weather conditions and its implication on surface ozone concentrations over the Pearl River Delta（PRD） and Yangtze River Delta（YRD） regions. Two scenarios of urban maps are used in the WRF-Chem to represent the early 1990s （pre-urbanization） and the current urban distribution in the PRD and the YRD. Month-long simulation results using the above land-use scenarios for March 2001 show that urbanization increases both the day- and night-time 2-m temperatures by about 0.6℃and 1.4℃, respectively. Daytime reduction in the wind speed by about 3.0 m s-1 is larger than that for the nighttime （0.5 to 2 m s-1）. The daytime increase in the PBL height （〉 200 m） is also larger than the nighttime （50-100 m）. The meteorological conditions modified by urbanization lead to detectable ozone-concentration changes in the PRD and the YRD. Urbanization increases the nighttime surface-ozone concentrations by about 4.7%-8.5% and by about 2.9%-4.2% for the daytime. In addition to modifying individual meteorological variables, urbanization also enhances the convergence zones, especially in the PRD. More importantly, urbanization has different effects on the surface ozone for the PRD and the YRD, presumably due to their urbanization characteristics and geographical locations. Even though the PRD has a smaller increase in the surface temperature than the YRD, it has （a） weaker surface wind speed, （b） smaller increase in PBL heights, and （c） stronger convergence zones. The latter three factors outweighed the temperature increase and resulted in a larger ozone enhancement in the PRD than the YRD.
文摘Placer diamond mining in the Anabar area involves various operations that cause long-term (nearly a quarter of a century) environmental impacts. The long history of mining activities, the technology used to mine the placers, as well as the poor assimilative capacity of the natural systems can result in serious environmental impacts in the area. The primary geochemical processes in the diamond-bearing area are affected by the occurrence of permafrost and relict ice, the lengthy duration of ice cover in water bodies, and the widespread development of cryogenic processes. This promotes physical migration of contaminants, cryogenic metamorphization of waters, and long-term accumulation of organic contaminants in low-temperature, reduction and sedimentation barriers. In this paper, some environmental and geochemical effects of diamond mining in the Arctic area are discussed.
文摘In 1999 aerosol samples were collected by cascade at Meteorological Tower in Beijing. The 12 group aerosol samples obtained were analyzed using PIXE method, which resulted in 20 elemental concentrations and size distribution of elemental concentrations. From the observation, the elemental concentrations, size distribution of elemental concentrations and their variations are analyzed. It shows that concentrations of the most elements in aerosols increase greatly compared with those in the past except that the concentrations of V, K, Sr, and the source of aerosols has changed greatly in the past decade. Fine mode aerosols increase more rapidly in the past decade, which may be due to the contribution of coal combustion and automobile exhaust. Pb content in aerosol is much higher than that at the beginning of 1980s, and has a decreasing trend in recent years because of using non leaded gasoline.
文摘Antibacterial ceramic was prepared by doping enamel slurry with composite phosphate inorganic antibacterial materials containing rare earth (inorganic antibacterial additives), and then the mechanisms for activating water and improving seed germinative property were tested by nuclear magnetic resonance (NMR) and the method of testing oxygen dissolved in activated water. Results show that the half peak width of (()^(17)O-NMR) for tap water activated by the antibacterial ceramic drops from 115.36 to 99.15 Hz, and oxygen concentrations of activated water increase by 20%, germinate rate of horsebean and earthnut seeds increases by 12.5% and 7.5%, respectively. Therefore antibacterial ceramic doped enamel slurry with inorganic antibacterial additives containing rare earth can reduce the volume of clusters of water molecules, improve activation of tap water, and promote plant seeds germinate.
