Climate change and anthropogenic activities have driven significant terrestrial water storage changes(TWSC)in the Three Rivers Source Region(TRSR),exerting profound impacts on freshwater availability across China and ...Climate change and anthropogenic activities have driven significant terrestrial water storage changes(TWSC)in the Three Rivers Source Region(TRSR),exerting profound impacts on freshwater availability across China and broader Asia.However,long-term TWSC characterization remains challenging due to limited observational data in this alpine region.Here,we integrate GRACE observations(2002-2020),ERA5-Land reanalysis,and GLDAS data to reconstruct TWSC using two methods:(1)the water balance method(PER)and(2)the component summation method(SS),applied to three input datasets(ERA5-Land,GLDAS,and their average,GLER).Comparative analysis reveals that the SS method applied to GL-ER yields the highest consistency with GRACE-derived TWSC.Using this optimal approach,we extend the analysis to 1951~2020,uncovering spatiotemporal TWSC patterns.Although annual TWSC trends appear negligible due to strong seasonality,we introduce the intra-year TWSC fluctuation(TWSCF)index to quantify cumulative variability.A significant(p<0.05)transition occurred in 1980,with TWSCF shifting from a declining trend(-0.39 mm/yr)to an increasing trend(0.56 mm/yr),primarily driven by soil moisture changes.However,Hurst exponent analysis suggests this upward trend may not persist.Drought and vegetation assessments indicate concurrent wetting and greening in the TRSR.TWSC correlates strongly with meteorological drought,acting as a reliable drought indicator while its linkage with vegetation dynamics suggests a potential contribution to greening.Our findings provide a robust framework for understanding long-term TWSC evolution and its hydrological-ecological interactions under climate change.展开更多
The effects of styrene-butadiene-styrene(SBS)pre-swelling/extraction process and the incorporation of C9 petroleum resin on the anti-aging performance of modified asphalt were systematically evaluated by characterizin...The effects of styrene-butadiene-styrene(SBS)pre-swelling/extraction process and the incorporation of C9 petroleum resin on the anti-aging performance of modified asphalt were systematically evaluated by characterizing the physical indexes,chemical compositions and rheological parameters.The experimental results show that the SBS pre-swelling/extraction process and the incorporation of C9 petroleum resin improve the dispersion performance of SBS in asphalt as well as the strength of SBS polymer network structures,and the synergistic effects decrease the volatilization degree of asphalt lightweight components and the degradation rate of SBS during the aging process.The anti-aging performance of SBS modified asphalt(SBSMA)was significantly enhanced by SBS pre-swelling/extraction process compounded with the incorporation of C9 petroleum resin,and the anti-aging effect was gradually enhanced with the increase of C9 petroleum resin content.展开更多
To overcome the limitations of traditional experimental“trial and error”methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular me...To overcome the limitations of traditional experimental“trial and error”methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular mechanism of the antioxidant reaction of hindered phenol,diphenylamine,and alkyl sulfide are studied via molecular simulations.Calculation results show that the strong electron-donating ability and high hydrogen-donating activity of the antioxidant molecule and the low hydrogen-abstracting activity of free radicals formed after dehydrogenation are the internal molecular causes of the shielding of phenol and diphenylamine from scavenging peroxy free radicals,and the strong electron-donating ability is the internal molecular cause of the high activity of thioether in decomposing alkyl hydrogen peroxide.Based on this antioxidant molecular mechanism,a molecular design rule of antioxidant is proposed,namely“high EHOMO,large Q(S),low bond dissociation energy BDE(O—H)and BDE(N—H)”.Two new antioxidants,PAS-I and PAS-II,are designed and prepared by chemical bonding of hindered phenol,diphenylamine,and sulfur atoms.Experimental results show that these antioxidants both have excellent antioxidant effects in lubricating oil,and that PAS-II is the superior antioxidant,consistent with theoretical predictions.展开更多
为合理评价污染场地风险,以我国云南省某铜堆浸场下游农田土为例,测定土壤中Cu、Pb、Cd和As等4种重金属总量,采用改进BCR(Bureau of European Communities Reference)连续提取法测定4种重金属赋存形态,分析4种重金属间的相关性,并使用...为合理评价污染场地风险,以我国云南省某铜堆浸场下游农田土为例,测定土壤中Cu、Pb、Cd和As等4种重金属总量,采用改进BCR(Bureau of European Communities Reference)连续提取法测定4种重金属赋存形态,分析4种重金属间的相关性,并使用地累积指数法、次生相与原生相比值法(RSP)和风险评价编码法(RAC)对场地土壤重金属污染和潜在风险程度进行评价。结果发现,重金属Cu、Pb、Cd和As平均的含量分别为39.50、46.98、0.16、82.67mg⋅kg^(-1),较云南省重金属背景值,4种重金属超标率分别为0、83.33%、33.33%和100.00%,其中As污染需要特别关注;提取重金属赋存形态结果显示,土样中Cu、Pb、Cd和As均以残渣态为主,占比为83.14%~95.62%,表明4种重金属均以稳定形态存在于土体中;对比3种评价方法,评价结果存在明显差异,地累积指数Igeo结果显示土壤仅As存在污染超标现象,其余3种重金属均无污染,次生相与原生相比值法结果显示,4种重金属对环境均无污染,而风险评价编码法结果显示,Cd对土壤环境存在低风险,其余3种重金属则无风险。对比发现,仅以污染场地土壤重金属总量作为评价指标会一定程度夸大污染风险,应综合重金属总量及赋存形态含量进行分析。虽然重金属元素污染总量较高,但活跃性重金属含量非常低,向环境中扩散的风险也非常低。因此,研究区重金属污染程度较轻,潜在生态风险为低风险。展开更多
To formulate fluids with flowback water,produced water directly to improve the utilization rate of recycling and reduce the adsorption damage of slick water to reservoirs,a high salt tolerance and low adsorption drag ...To formulate fluids with flowback water,produced water directly to improve the utilization rate of recycling and reduce the adsorption damage of slick water to reservoirs,a high salt tolerance and low adsorption drag reducer was designed and prepared by introducing polar cation fragments to enhance the non-covalent interactions between the chains.The drag reducer was characterized by IR and NMR.Friction resistance and viscosity tests were conducted to evaluate its salt resistance property.Static adsorption and dynamic adsorption retention tests were carried out to evaluate the damage of this reducer to shale reservoirs.The introduction of cation units into the molecular structure can weak the shielding effect of metal cations to some extent,so the drag reducer can keep a stable molecular structure and good resistant reducing performance under high salinity.The enhancement of non-covalent interaction between chains decreased the free polarity sites,further reduced the possibility of hydrogen bonding between drag reducer molecules and shale.In high salinity condition,both the adsorption capacity of the drag reducer on the shale surface and the average damage rate to the core permeability are low.Compared with the conventional salt-tolerant system,the overall liquid cost was reduced by 17%and the production per well increased by 44%.The application of this slick water system has achieved remarkable results.展开更多
基金funded by the Postdoctoral Research Startup Foundation of University of Jinan(Grant No.100389917).
文摘Climate change and anthropogenic activities have driven significant terrestrial water storage changes(TWSC)in the Three Rivers Source Region(TRSR),exerting profound impacts on freshwater availability across China and broader Asia.However,long-term TWSC characterization remains challenging due to limited observational data in this alpine region.Here,we integrate GRACE observations(2002-2020),ERA5-Land reanalysis,and GLDAS data to reconstruct TWSC using two methods:(1)the water balance method(PER)and(2)the component summation method(SS),applied to three input datasets(ERA5-Land,GLDAS,and their average,GLER).Comparative analysis reveals that the SS method applied to GL-ER yields the highest consistency with GRACE-derived TWSC.Using this optimal approach,we extend the analysis to 1951~2020,uncovering spatiotemporal TWSC patterns.Although annual TWSC trends appear negligible due to strong seasonality,we introduce the intra-year TWSC fluctuation(TWSCF)index to quantify cumulative variability.A significant(p<0.05)transition occurred in 1980,with TWSCF shifting from a declining trend(-0.39 mm/yr)to an increasing trend(0.56 mm/yr),primarily driven by soil moisture changes.However,Hurst exponent analysis suggests this upward trend may not persist.Drought and vegetation assessments indicate concurrent wetting and greening in the TRSR.TWSC correlates strongly with meteorological drought,acting as a reliable drought indicator while its linkage with vegetation dynamics suggests a potential contribution to greening.Our findings provide a robust framework for understanding long-term TWSC evolution and its hydrological-ecological interactions under climate change.
基金Fnded by the National Key Research and Development Program of China(No.2023YFC3807202)the Key Research and Development Plan in Hubei Province of China(Nos.2022BCA082 and 2024BAB108)the Annual Research Project of China Railway Construction Corporation(No.2023-B03)。
文摘The effects of styrene-butadiene-styrene(SBS)pre-swelling/extraction process and the incorporation of C9 petroleum resin on the anti-aging performance of modified asphalt were systematically evaluated by characterizing the physical indexes,chemical compositions and rheological parameters.The experimental results show that the SBS pre-swelling/extraction process and the incorporation of C9 petroleum resin improve the dispersion performance of SBS in asphalt as well as the strength of SBS polymer network structures,and the synergistic effects decrease the volatilization degree of asphalt lightweight components and the degradation rate of SBS during the aging process.The anti-aging performance of SBS modified asphalt(SBSMA)was significantly enhanced by SBS pre-swelling/extraction process compounded with the incorporation of C9 petroleum resin,and the anti-aging effect was gradually enhanced with the increase of C9 petroleum resin content.
文摘To overcome the limitations of traditional experimental“trial and error”methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular mechanism of the antioxidant reaction of hindered phenol,diphenylamine,and alkyl sulfide are studied via molecular simulations.Calculation results show that the strong electron-donating ability and high hydrogen-donating activity of the antioxidant molecule and the low hydrogen-abstracting activity of free radicals formed after dehydrogenation are the internal molecular causes of the shielding of phenol and diphenylamine from scavenging peroxy free radicals,and the strong electron-donating ability is the internal molecular cause of the high activity of thioether in decomposing alkyl hydrogen peroxide.Based on this antioxidant molecular mechanism,a molecular design rule of antioxidant is proposed,namely“high EHOMO,large Q(S),low bond dissociation energy BDE(O—H)and BDE(N—H)”.Two new antioxidants,PAS-I and PAS-II,are designed and prepared by chemical bonding of hindered phenol,diphenylamine,and sulfur atoms.Experimental results show that these antioxidants both have excellent antioxidant effects in lubricating oil,and that PAS-II is the superior antioxidant,consistent with theoretical predictions.
文摘为合理评价污染场地风险,以我国云南省某铜堆浸场下游农田土为例,测定土壤中Cu、Pb、Cd和As等4种重金属总量,采用改进BCR(Bureau of European Communities Reference)连续提取法测定4种重金属赋存形态,分析4种重金属间的相关性,并使用地累积指数法、次生相与原生相比值法(RSP)和风险评价编码法(RAC)对场地土壤重金属污染和潜在风险程度进行评价。结果发现,重金属Cu、Pb、Cd和As平均的含量分别为39.50、46.98、0.16、82.67mg⋅kg^(-1),较云南省重金属背景值,4种重金属超标率分别为0、83.33%、33.33%和100.00%,其中As污染需要特别关注;提取重金属赋存形态结果显示,土样中Cu、Pb、Cd和As均以残渣态为主,占比为83.14%~95.62%,表明4种重金属均以稳定形态存在于土体中;对比3种评价方法,评价结果存在明显差异,地累积指数Igeo结果显示土壤仅As存在污染超标现象,其余3种重金属均无污染,次生相与原生相比值法结果显示,4种重金属对环境均无污染,而风险评价编码法结果显示,Cd对土壤环境存在低风险,其余3种重金属则无风险。对比发现,仅以污染场地土壤重金属总量作为评价指标会一定程度夸大污染风险,应综合重金属总量及赋存形态含量进行分析。虽然重金属元素污染总量较高,但活跃性重金属含量非常低,向环境中扩散的风险也非常低。因此,研究区重金属污染程度较轻,潜在生态风险为低风险。
基金Supported by the China National Science and Technology Major Project(2017ZX05023003)National Science Fund for Distinguished Young Scholars(51525404)
文摘To formulate fluids with flowback water,produced water directly to improve the utilization rate of recycling and reduce the adsorption damage of slick water to reservoirs,a high salt tolerance and low adsorption drag reducer was designed and prepared by introducing polar cation fragments to enhance the non-covalent interactions between the chains.The drag reducer was characterized by IR and NMR.Friction resistance and viscosity tests were conducted to evaluate its salt resistance property.Static adsorption and dynamic adsorption retention tests were carried out to evaluate the damage of this reducer to shale reservoirs.The introduction of cation units into the molecular structure can weak the shielding effect of metal cations to some extent,so the drag reducer can keep a stable molecular structure and good resistant reducing performance under high salinity.The enhancement of non-covalent interaction between chains decreased the free polarity sites,further reduced the possibility of hydrogen bonding between drag reducer molecules and shale.In high salinity condition,both the adsorption capacity of the drag reducer on the shale surface and the average damage rate to the core permeability are low.Compared with the conventional salt-tolerant system,the overall liquid cost was reduced by 17%and the production per well increased by 44%.The application of this slick water system has achieved remarkable results.
