Great potential of underground gas/energy storage in salt caverns seems to be a promising solution to support renewable energy.In the underground storage method,the operating cycle unfortunately may reach up to daily ...Great potential of underground gas/energy storage in salt caverns seems to be a promising solution to support renewable energy.In the underground storage method,the operating cycle unfortunately may reach up to daily or even hourly,which generates complicated pressures on the salt cavern.Furthermore,the mechanical behavior of rock salt may change and present distinct failure characteristics under different stress states,which affects the performance of salt cavern during the time period of full service.To reproduce a similar loading condition on the cavern surrounding rock mass,the cyclic triaxial loading/unloading tests are performed on the rock salt to explore the mechanical transition behavior and failure characteristics under different confinement.Experimental results show that the rock salt samples pre-sent a diffused shear failure band with significant bulges at certain locations in low confining pressure conditions(e.g.5 MPa,10 MPa and 15 MPa),which is closely related to crystal misorientation and grain boundary sliding.Under the elevated confinement(e.g.20 MPa,30 MPa and 40 MPa),the dilation band dominates the failure mechanism,where the large-size halite crystals are crushed to be smaller size and new pores are developing.The failure transition mechanism revealed in the paper provides additional insight into the mechanical performance of salt caverns influenced by complicated stress states.展开更多
Zabuye Salt Lake(ZSL)in Xizang is the only saline lake in the world with natural crystalline lithium carbonate.As it is an important lithium production base in China,any changes of this lake are concerning.Global clim...Zabuye Salt Lake(ZSL)in Xizang is the only saline lake in the world with natural crystalline lithium carbonate.As it is an important lithium production base in China,any changes of this lake are concerning.Global climate change(CC)has affected the hydrological conditions of glaciers,lakes,and ecosystems in the Tibetan Plateau(TP).With the aim of monitoring dynamic hydrological changes in ZSL and Lunggar Glaciers(LG)to identify factors governing lake changes,and to estimate the potential damage to grasslands and salt pans,Landsat remote sensing(RS)and meteorological data were used to do a series of experiments and analysis.Firstly,according to the spectral characteristics(SC),salt lake,glaciers,grasslands,and salt pans around the salt lake were extracted by band calculation(BC).Secondly,basin and water areas of the expanded lake were estimated using a shuttle radar topography mission(SRTM)digital elevation model(DEM).Thirdly,comprehensive analyses of lake and glacier area changes,and regional meteorological factors(annual average temperature,annual precipitation,and evaporation)were performed,and the results show that ZSL expanded at a rate of 5.28 km^(2)/a,it is likely to continue expanding.Expansion was closely related to the large-scale melting of a glacier caused by rising temperatures.Continued lake expansion(LE)will exert different effects on surrounding grasslands and salt pans,7.84 km^(2)of grassland and 2.7 km^(2)of salt pan will be submerged with every meter of water increase in the lake.Similar prediction methods was used to monitor other lakes on the TP.Mami Co,Selin Co,and Chaerhan salt lakes all expanded at different rates,and may potentially cause different levels of potential harm to surrounding grasslands and roads.Our study contributes to salt lake research and demonstrates the superiority of RS technology for monitoring saline lakes.展开更多
Background The impairment of social function is widespread in the patients with chronic schizophrenia, which seriously affects family, life and work conditions.Aims The main purpose of this study was to investigate th...Background The impairment of social function is widespread in the patients with chronic schizophrenia, which seriously affects family, life and work conditions.Aims The main purpose of this study was to investigate the efficacy of paliperidone in the treatment of social function in chronic schizophrenia.Methods A total of 81 patients who met the standard criteria for schizophrenia and long-term hospitalised inpatients were randomly divided into the treatment group and normal control group following a 1-year prospective follow-up study. The reatment group(41 cases) used paliperidone extended-release tablets for reducing dosage, as appropriate, based on the original treatment strategy; and the control group(40 cases) used the former drugs. All patients were assessed using the Positive and Negative Symptom Scales(PANSS), and the Treatment Emergent Symptom Scale(TESS) was used to assess adverse drug reactions. The Hospitalised Psychiatric Patients' Social Functions Rating Scale(SSPI) was used to assess social function of participants before and after 8 weeks, 6 months and 1 year of treatment.Results At baseline there were no significant differences between the two groups in age, duration of illness, educational background and dosage of antipsychotic drugs(converted into chlorpromazine equivalency). There was statistically significant difference in PANSS positive symptoms by interaction effect(Fgroup×time=18.24, df=3237, p<0.001) and time effect(Ftime=21.66, df=3, p<0.01) and the difference in PANSS positive symptoms by grouping effect(Fgroup=0.68, df=1, p=0.41) was not statistically significant. The difference of grouping effect of PANSS negative symptoms(Fgroup=9.93, df=1, p=0.002), time effect(Ftime=279.15, df=3, p<0.001) and interaction effect(Fgroup×time=279.15, df=3237, p<0.001) were statistically significant. There were statistically significant differences in the grouping effect(Fgroup=6.59, df=1, p=0.012), time effect(Ftime=152.97, df=3, p<0.001) and interaction effect(Fgroup×time=148.82, df=3237, p<0.001) of PANSS general pathological symptoms, the same as the total score of the PANSS, which showed large differences in grouping effect(Fgroup=7.04, df=1, p=0.001), time effect(Ftime=210.78, df=3, p<0.001) and interaction effect(Fgroup×time=205.20, df=3237, p<0.01). We found in the total SSPI score, grouping effect(Fgroup=31.70, df=1, p<0.001), time effect(Ftime=161.84, df=3, p<0.001) and interaction effect(Fgroup×time=132.74, df=3237, p<0.001) were demonstrated to be significantly different. Even though adverse reactionsoccurred 7 times in the treatment group and 44 times in the control group based on the Treatment Emergent Symptom Scale(TESS), incidence rate was significantly lower than that of the control group(χ2=18.854, p<0.001).Conclusion Paliperidone can safely and effectively improve negative symptoms and social function in patients with chronic schizophrenia.展开更多
The binding interactions between 4-aminopyridine(4-AP) and a series of cucurbit[n]urils(Q[5], Q[6],TMe Q[6], Q[7], Q[8]) have been studied using1H NMR spectroscopy, UV–vis absorption spectroscopy,isothermal titration...The binding interactions between 4-aminopyridine(4-AP) and a series of cucurbit[n]urils(Q[5], Q[6],TMe Q[6], Q[7], Q[8]) have been studied using1H NMR spectroscopy, UV–vis absorption spectroscopy,isothermal titration calorimetry(ITC) and X-ray crystallography. The data indicates that the Q[5]@4-AP complex exhibits exo binding, which is not observed in the other four host-guest complexes. Furthermore,X-ray crystallography clearly reveals how the Q[n]s bind with 4-AP to form complexes, for example Q[5]forms an outer-surface complex, whilst Q[6], TMe Q[6] and Q[7] formed 1:1 host and guest type complexes, and Q[8] formed a stable 1:2 ternary complex due to its large cavity, which can accommodate two 4-AP molecules.展开更多
Strategic emerging minerals such as lithium,beryllium,niobium and tantalum are the most important rare metals currently,especially with the increasing demand of emerging industries on rare metals in China.The Jiajika ...Strategic emerging minerals such as lithium,beryllium,niobium and tantalum are the most important rare metals currently,especially with the increasing demand of emerging industries on rare metals in China.The Jiajika deposit with a complete Li-Be-Nb-Ta metallogenic series is the largest pegmatite type rare metal deposit in China at present.In this paper,systematic researches of geochronology and petrogeochemistry were carried out to understand the genetic relationships between mineralization and magma evolution in the Jiajika deposit,which might be helpful to further rare-element prospecting in Songpan-Garze area.Zircon LA-ICP-MS U-Pb dating yields a concordia age of 217±1.1 Ma and a weighted mean 206 Pb/238 U age of 217±0.84 Ma for the aplite from the No.308 pegmatite.Cassiterite LA-MC-ICPMS dating yields concordant ages of 211±4.6 Ma for the No.308 pegmatite vein and198±4.4 Ma for the No.133 pegmatite vein,indicating that the rare metal mineralization mainly occurred in the Late Indosinian Period,further suggesting that the granites,aplites and pegmatites in Jiajika formed during a relatively stable stage after the intense orogeny of the Indosinian cycle.The rare metal-bearing granitic rocks and pegmatites show a clear linear relationship between A/CNK and A/NK and are enriched in total alkalis and depleted in CaO,FeO,MnO,MgO,Ba and Sr.All barren rocks and mineralized rocks feature similar rare earth element and trace element geochemical patterns.Thus,these characteristics indicate that the aplites and pegmatites represent the highly differentiated products of the two-mica granite(MaG)in this area,which is the most likely parent magma.During the evolution of magma,strong alkali metasomatism occurred between the melt phase and the volatile-rich fluid phase;as a result,large-scale rare metal mineralization occurred in certain structural zones of the pegmatite veins in the Jiajika deposit.展开更多
A novel fluorescent sensor was prepared from sulfonated calix[4]arene(SC4A)by the host-guest com-plexation method using the fluorescent dye rhodamine B(RB)as a structure-directing agent.The crystal structure of the ho...A novel fluorescent sensor was prepared from sulfonated calix[4]arene(SC4A)by the host-guest com-plexation method using the fluorescent dye rhodamine B(RB)as a structure-directing agent.The crystal structure of the host-guest complex(RB@(SC4A)_(3))was confirmed by X-ray diffraction studies while its performance and sensing mechanism for metal ion pollutants were characterized using fluorescence and nuclear magnetic resonance spectroscopies.The results showed that RB@(SC4A)_(3) had a triangular branch structure resulting from host-guest mediation of the interactions between the three SC4A host molecules and the three terminal groups of the guest molecule RB.The host-guest complex exhibited sensitive and selective sensing towards Fe^(3+)ions via a fluorescence quenching mechanism.The results indicated that RB@(SC4A)_(3) could be a promising sensitive and selective fluorescent sensor for metal ion pollutants mon-itoring.It also provided new insights into the synthesis of calixarene-based host-guest complex.展开更多
Ion-absorption rare earth ores are an important mineral resource in China.Nowadays,the unauthorized mining has become a serious problem,resulting in severe water pollution and the wastage of rare earth elements(REEs)....Ion-absorption rare earth ores are an important mineral resource in China.Nowadays,the unauthorized mining has become a serious problem,resulting in severe water pollution and the wastage of rare earth elements(REEs).Being able to estimate the concentration of dissolved REEs in water bodies near mines is essential for tackling this environmental problem.Conventionally,quantitative analyses of the contents of dissolved REEs are performed using laboratory-based techniques,which can be time consuming and costly.Spectral reflectance is a rapid and cost-effective means of characterizing the chemical compositions of light-absorbing materials.In this study,reflectance spectroscopy was performed on dissolved REEs,and the correlation between their reflectance characteristics and REE content was determined.A total of 50 aqueous media samples collected in south Jiangxi Province and 25 laboratory-produced aqueous media samples were tested,and their reflectance spectra and REE contents were measured using reflectance spectroscopy and inductively coupled plasma mass spectrometry,respectively.Next,the reflectance,differential reflectance,and absorption depth were analysed based on the REE content.Six diagnostic absorption features related to REEs are recognised in the visible and near-infrared wavelength regions,along with several smaller peaks.It indicates that the results of the absorption depth analysis are in accordance with the absorption spectra characteristics of the REEs,with the R2 value being higher than 0.97.The intensity of each of the six absorption bands exhibits a linear correlation to the total REE content.Therefore,linear regressio n models can be derived for estimating the total concentration of REEs in aqueous media samples.What’s more,the detection limit for REEs is determined to be about 30μg/L.Thus,it can be concluded that reflectance spectroscopy is a suitable technique for estimating the concentration of dissolved REEs.展开更多
Technology is an instrument to build BRI relationships,mitigate the environmental and climate impacts of BRI projects,as well as to enhance environmental sustainability in the regions.This study aims to reposition Chi...Technology is an instrument to build BRI relationships,mitigate the environmental and climate impacts of BRI projects,as well as to enhance environmental sustainability in the regions.This study aims to reposition China in global climate technology transfer in BRI era and to obtain initial knowledge on needs,priorities,and barriers from the receivers’perspective.Focus group method with aid of questionnaire survey and follow-up face-to-face interviews was adopted to capture the major issues directly expressed by receivers from these countries.A total of 63 valid questionnaires were collected,and 13 respondents were face-to-face interviewed.The results confirmed that energy and agriculture were the most prioritized sectors for mitigation and adaptation in the developing countries alongside OBOR.The prioritized technologies for mitigation included cogeneration,solar photovoltaic,and biomass/biogas electricity.Irrigation,conservation agriculture,and soil management were prioritized for adaptation in agricultural sector,and water recycling and reuse,source water protection,and urban drainage management in water resource sector.Technology cost during installation and operation was stressed as the most important factor constraining the application and diffusion of climate technologies.But communication including language,information,and ways of communication,was also identified as an important factor.This implied that the conventional climate technology transfer need adapt to changing contexts of BRI and be complemented with innovative approaches involving multi-actors in different phases of climate technology development.Due to the limited representativeness of the sample,the results can hardly be generalized to all the countries,but raised interesting topics for future researches.展开更多
Carbon dots are rapidly emerging carbon-based nanomaterials that,due to their growing applications,will inevitable find their way to natural waters;however,their environmental fate is mostly unknown.Carbon dots with d...Carbon dots are rapidly emerging carbon-based nanomaterials that,due to their growing applications,will inevitable find their way to natural waters;however,their environmental fate is mostly unknown.Carbon dots with different surface functionality were fabricated and characterized by TEM and FT-IR.Their surface charge,given by the zeta potential,and their hydrodynamic diameter in suspension were investigated under a variety of environmentally relevant conditions.The effect of ionic strength was studied in the presence of monovalent(NaCl)and divalent(CaCl_2)cations,for p H levels from 3 to 11;humic acid was used as a model for dissolved natural organic matter.Total potential energies of interactions were modeled by classical DLVO theory.The experimental results showed that water chemistry altered the surface charge of the nanomaterials,but their hydrodynamic size could not be correlated to those changes.Evidence of specific interactions was found for the amino functionalized particles in most cases,as well as the plain carbon dots in the presence of Ca^(2+)and humic acid.Nanoparticles remained largely stable in suspension,with some exception at the highest ionic strength considered.DLVO theory did not adequately capture the aggregation behavior of the system.Moreover,cation and/or humic acid adsorption negatively affected the emission intensity of the particles,suggesting limitations to their use in natural water sensing applications.The particular stability shown by the carbon dots results in exposure to organisms in the water column and the possibility of contamination transported to significant distances from their source.展开更多
基金This research was financially supported by the Science and Technology Department of Sichuan Province Project,China(Grant Nos.2022YFSY0007,2021YFH0010)the National Scientific Science Foundation of China(Grant No.U20A20266).
文摘Great potential of underground gas/energy storage in salt caverns seems to be a promising solution to support renewable energy.In the underground storage method,the operating cycle unfortunately may reach up to daily or even hourly,which generates complicated pressures on the salt cavern.Furthermore,the mechanical behavior of rock salt may change and present distinct failure characteristics under different stress states,which affects the performance of salt cavern during the time period of full service.To reproduce a similar loading condition on the cavern surrounding rock mass,the cyclic triaxial loading/unloading tests are performed on the rock salt to explore the mechanical transition behavior and failure characteristics under different confinement.Experimental results show that the rock salt samples pre-sent a diffused shear failure band with significant bulges at certain locations in low confining pressure conditions(e.g.5 MPa,10 MPa and 15 MPa),which is closely related to crystal misorientation and grain boundary sliding.Under the elevated confinement(e.g.20 MPa,30 MPa and 40 MPa),the dilation band dominates the failure mechanism,where the large-size halite crystals are crushed to be smaller size and new pores are developing.The failure transition mechanism revealed in the paper provides additional insight into the mechanical performance of salt caverns influenced by complicated stress states.
基金Supported by the Academician Workstation Projects of the Institute of Mineral Resources,Chinese Academy of Geological Sciences(Nos.HE 2205,HE 2206,KK 2012)the National Natural Science Foundation of China(No.42172332)+1 种基金the China Geological Survey Project(No.DD 20221684)the Basic Research Projects of the Institute of Mineral Resources,Chinese Academy of Geological Sciences(No.KK 2102)。
文摘Zabuye Salt Lake(ZSL)in Xizang is the only saline lake in the world with natural crystalline lithium carbonate.As it is an important lithium production base in China,any changes of this lake are concerning.Global climate change(CC)has affected the hydrological conditions of glaciers,lakes,and ecosystems in the Tibetan Plateau(TP).With the aim of monitoring dynamic hydrological changes in ZSL and Lunggar Glaciers(LG)to identify factors governing lake changes,and to estimate the potential damage to grasslands and salt pans,Landsat remote sensing(RS)and meteorological data were used to do a series of experiments and analysis.Firstly,according to the spectral characteristics(SC),salt lake,glaciers,grasslands,and salt pans around the salt lake were extracted by band calculation(BC).Secondly,basin and water areas of the expanded lake were estimated using a shuttle radar topography mission(SRTM)digital elevation model(DEM).Thirdly,comprehensive analyses of lake and glacier area changes,and regional meteorological factors(annual average temperature,annual precipitation,and evaporation)were performed,and the results show that ZSL expanded at a rate of 5.28 km^(2)/a,it is likely to continue expanding.Expansion was closely related to the large-scale melting of a glacier caused by rising temperatures.Continued lake expansion(LE)will exert different effects on surrounding grasslands and salt pans,7.84 km^(2)of grassland and 2.7 km^(2)of salt pan will be submerged with every meter of water increase in the lake.Similar prediction methods was used to monitor other lakes on the TP.Mami Co,Selin Co,and Chaerhan salt lakes all expanded at different rates,and may potentially cause different levels of potential harm to surrounding grasslands and roads.Our study contributes to salt lake research and demonstrates the superiority of RS technology for monitoring saline lakes.
基金supported in part by the National Science Fund of China(81771450,81471358)Shanghai Health Bureau scientific research grant(201540029)Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant(20152530)
文摘Background The impairment of social function is widespread in the patients with chronic schizophrenia, which seriously affects family, life and work conditions.Aims The main purpose of this study was to investigate the efficacy of paliperidone in the treatment of social function in chronic schizophrenia.Methods A total of 81 patients who met the standard criteria for schizophrenia and long-term hospitalised inpatients were randomly divided into the treatment group and normal control group following a 1-year prospective follow-up study. The reatment group(41 cases) used paliperidone extended-release tablets for reducing dosage, as appropriate, based on the original treatment strategy; and the control group(40 cases) used the former drugs. All patients were assessed using the Positive and Negative Symptom Scales(PANSS), and the Treatment Emergent Symptom Scale(TESS) was used to assess adverse drug reactions. The Hospitalised Psychiatric Patients' Social Functions Rating Scale(SSPI) was used to assess social function of participants before and after 8 weeks, 6 months and 1 year of treatment.Results At baseline there were no significant differences between the two groups in age, duration of illness, educational background and dosage of antipsychotic drugs(converted into chlorpromazine equivalency). There was statistically significant difference in PANSS positive symptoms by interaction effect(Fgroup×time=18.24, df=3237, p<0.001) and time effect(Ftime=21.66, df=3, p<0.01) and the difference in PANSS positive symptoms by grouping effect(Fgroup=0.68, df=1, p=0.41) was not statistically significant. The difference of grouping effect of PANSS negative symptoms(Fgroup=9.93, df=1, p=0.002), time effect(Ftime=279.15, df=3, p<0.001) and interaction effect(Fgroup×time=279.15, df=3237, p<0.001) were statistically significant. There were statistically significant differences in the grouping effect(Fgroup=6.59, df=1, p=0.012), time effect(Ftime=152.97, df=3, p<0.001) and interaction effect(Fgroup×time=148.82, df=3237, p<0.001) of PANSS general pathological symptoms, the same as the total score of the PANSS, which showed large differences in grouping effect(Fgroup=7.04, df=1, p=0.001), time effect(Ftime=210.78, df=3, p<0.001) and interaction effect(Fgroup×time=205.20, df=3237, p<0.01). We found in the total SSPI score, grouping effect(Fgroup=31.70, df=1, p<0.001), time effect(Ftime=161.84, df=3, p<0.001) and interaction effect(Fgroup×time=132.74, df=3237, p<0.001) were demonstrated to be significantly different. Even though adverse reactionsoccurred 7 times in the treatment group and 44 times in the control group based on the Treatment Emergent Symptom Scale(TESS), incidence rate was significantly lower than that of the control group(χ2=18.854, p<0.001).Conclusion Paliperidone can safely and effectively improve negative symptoms and social function in patients with chronic schizophrenia.
基金supported by the Innovation Program for Highlevel Talents of Guizhou Province (No. 2016-5657)the University of Hull for support。
文摘The binding interactions between 4-aminopyridine(4-AP) and a series of cucurbit[n]urils(Q[5], Q[6],TMe Q[6], Q[7], Q[8]) have been studied using1H NMR spectroscopy, UV–vis absorption spectroscopy,isothermal titration calorimetry(ITC) and X-ray crystallography. The data indicates that the Q[5]@4-AP complex exhibits exo binding, which is not observed in the other four host-guest complexes. Furthermore,X-ray crystallography clearly reveals how the Q[n]s bind with 4-AP to form complexes, for example Q[5]forms an outer-surface complex, whilst Q[6], TMe Q[6] and Q[7] formed 1:1 host and guest type complexes, and Q[8] formed a stable 1:2 ternary complex due to its large cavity, which can accommodate two 4-AP molecules.
基金supported by the National Key Research and Develpoment Program of China (No. 2017YFC0602701)the China Postdoctoral Science Foundation (No. 2017M610960)the China Geological Survey’s projects (Nos. DD20190173 and DD20190379)
文摘Strategic emerging minerals such as lithium,beryllium,niobium and tantalum are the most important rare metals currently,especially with the increasing demand of emerging industries on rare metals in China.The Jiajika deposit with a complete Li-Be-Nb-Ta metallogenic series is the largest pegmatite type rare metal deposit in China at present.In this paper,systematic researches of geochronology and petrogeochemistry were carried out to understand the genetic relationships between mineralization and magma evolution in the Jiajika deposit,which might be helpful to further rare-element prospecting in Songpan-Garze area.Zircon LA-ICP-MS U-Pb dating yields a concordia age of 217±1.1 Ma and a weighted mean 206 Pb/238 U age of 217±0.84 Ma for the aplite from the No.308 pegmatite.Cassiterite LA-MC-ICPMS dating yields concordant ages of 211±4.6 Ma for the No.308 pegmatite vein and198±4.4 Ma for the No.133 pegmatite vein,indicating that the rare metal mineralization mainly occurred in the Late Indosinian Period,further suggesting that the granites,aplites and pegmatites in Jiajika formed during a relatively stable stage after the intense orogeny of the Indosinian cycle.The rare metal-bearing granitic rocks and pegmatites show a clear linear relationship between A/CNK and A/NK and are enriched in total alkalis and depleted in CaO,FeO,MnO,MgO,Ba and Sr.All barren rocks and mineralized rocks feature similar rare earth element and trace element geochemical patterns.Thus,these characteristics indicate that the aplites and pegmatites represent the highly differentiated products of the two-mica granite(MaG)in this area,which is the most likely parent magma.During the evolution of magma,strong alkali metasomatism occurred between the melt phase and the volatile-rich fluid phase;as a result,large-scale rare metal mineralization occurred in certain structural zones of the pegmatite veins in the Jiajika deposit.
基金the National Natural Science Foundation of China (NSFC, No. 21861011)the Innovation Program for High-level Talents of Guizhou Province (No. 2016–5657) are gratefully acknowledged for financial support
文摘A novel fluorescent sensor was prepared from sulfonated calix[4]arene(SC4A)by the host-guest com-plexation method using the fluorescent dye rhodamine B(RB)as a structure-directing agent.The crystal structure of the host-guest complex(RB@(SC4A)_(3))was confirmed by X-ray diffraction studies while its performance and sensing mechanism for metal ion pollutants were characterized using fluorescence and nuclear magnetic resonance spectroscopies.The results showed that RB@(SC4A)_(3) had a triangular branch structure resulting from host-guest mediation of the interactions between the three SC4A host molecules and the three terminal groups of the guest molecule RB.The host-guest complex exhibited sensitive and selective sensing towards Fe^(3+)ions via a fluorescence quenching mechanism.The results indicated that RB@(SC4A)_(3) could be a promising sensitive and selective fluorescent sensor for metal ion pollutants mon-itoring.It also provided new insights into the synthesis of calixarene-based host-guest complex.
基金supported by the China Geological Survey Project(DD20190379)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20070304)+3 种基金the Fundamental Research Funds for the Institute of Mineral ResourcesChinese Academy of Geological Sciences(KK1919)the Fundamental Research Funds for the Institute of GeologyChinese Academy of Geological Sciences(J2004)。
文摘Ion-absorption rare earth ores are an important mineral resource in China.Nowadays,the unauthorized mining has become a serious problem,resulting in severe water pollution and the wastage of rare earth elements(REEs).Being able to estimate the concentration of dissolved REEs in water bodies near mines is essential for tackling this environmental problem.Conventionally,quantitative analyses of the contents of dissolved REEs are performed using laboratory-based techniques,which can be time consuming and costly.Spectral reflectance is a rapid and cost-effective means of characterizing the chemical compositions of light-absorbing materials.In this study,reflectance spectroscopy was performed on dissolved REEs,and the correlation between their reflectance characteristics and REE content was determined.A total of 50 aqueous media samples collected in south Jiangxi Province and 25 laboratory-produced aqueous media samples were tested,and their reflectance spectra and REE contents were measured using reflectance spectroscopy and inductively coupled plasma mass spectrometry,respectively.Next,the reflectance,differential reflectance,and absorption depth were analysed based on the REE content.Six diagnostic absorption features related to REEs are recognised in the visible and near-infrared wavelength regions,along with several smaller peaks.It indicates that the results of the absorption depth analysis are in accordance with the absorption spectra characteristics of the REEs,with the R2 value being higher than 0.97.The intensity of each of the six absorption bands exhibits a linear correlation to the total REE content.Therefore,linear regressio n models can be derived for estimating the total concentration of REEs in aqueous media samples.What’s more,the detection limit for REEs is determined to be about 30μg/L.Thus,it can be concluded that reflectance spectroscopy is a suitable technique for estimating the concentration of dissolved REEs.
基金This work was supported by the National Key R&D Program of China[2018YFA0606503].
文摘Technology is an instrument to build BRI relationships,mitigate the environmental and climate impacts of BRI projects,as well as to enhance environmental sustainability in the regions.This study aims to reposition China in global climate technology transfer in BRI era and to obtain initial knowledge on needs,priorities,and barriers from the receivers’perspective.Focus group method with aid of questionnaire survey and follow-up face-to-face interviews was adopted to capture the major issues directly expressed by receivers from these countries.A total of 63 valid questionnaires were collected,and 13 respondents were face-to-face interviewed.The results confirmed that energy and agriculture were the most prioritized sectors for mitigation and adaptation in the developing countries alongside OBOR.The prioritized technologies for mitigation included cogeneration,solar photovoltaic,and biomass/biogas electricity.Irrigation,conservation agriculture,and soil management were prioritized for adaptation in agricultural sector,and water recycling and reuse,source water protection,and urban drainage management in water resource sector.Technology cost during installation and operation was stressed as the most important factor constraining the application and diffusion of climate technologies.But communication including language,information,and ways of communication,was also identified as an important factor.This implied that the conventional climate technology transfer need adapt to changing contexts of BRI and be complemented with innovative approaches involving multi-actors in different phases of climate technology development.Due to the limited representativeness of the sample,the results can hardly be generalized to all the countries,but raised interesting topics for future researches.
文摘Carbon dots are rapidly emerging carbon-based nanomaterials that,due to their growing applications,will inevitable find their way to natural waters;however,their environmental fate is mostly unknown.Carbon dots with different surface functionality were fabricated and characterized by TEM and FT-IR.Their surface charge,given by the zeta potential,and their hydrodynamic diameter in suspension were investigated under a variety of environmentally relevant conditions.The effect of ionic strength was studied in the presence of monovalent(NaCl)and divalent(CaCl_2)cations,for p H levels from 3 to 11;humic acid was used as a model for dissolved natural organic matter.Total potential energies of interactions were modeled by classical DLVO theory.The experimental results showed that water chemistry altered the surface charge of the nanomaterials,but their hydrodynamic size could not be correlated to those changes.Evidence of specific interactions was found for the amino functionalized particles in most cases,as well as the plain carbon dots in the presence of Ca^(2+)and humic acid.Nanoparticles remained largely stable in suspension,with some exception at the highest ionic strength considered.DLVO theory did not adequately capture the aggregation behavior of the system.Moreover,cation and/or humic acid adsorption negatively affected the emission intensity of the particles,suggesting limitations to their use in natural water sensing applications.The particular stability shown by the carbon dots results in exposure to organisms in the water column and the possibility of contamination transported to significant distances from their source.
