As an important component of secondary aerosols,sulfate plays a crucial role in regulating atmospheric radiative balance and influencing the secondary formation of ozone(O_(3)).In real atmosphere,atmospheric oxidants ...As an important component of secondary aerosols,sulfate plays a crucial role in regulating atmospheric radiative balance and influencing the secondary formation of ozone(O_(3)).In real atmosphere,atmospheric oxidants NO_(2)and O_(3)can promote the oxidation of SO_(2)to form sulfate(SO_(4)^(2−))through multiphase chemistry that occur at different time scales.Due to the combined impact of meteorology,pollution sources,atmospheric chemistry,etc.,time-scale dependence of SO_(2)-SO_(4)^(2−)conversion makes the impact of NO_(2)/O_(3)on it more complex.In this study,based on long-term time series(2013-2020)of air pollution variables from seven stations in Hong Kong,the Multifractal Detrended Cross-Correlation Analysis(MFDCCA)method has been employed to quantify the cross-correlations between SO_(2)and SO_(4)^(2−)in real atmosphere at different time scales,for examining the time-scale dependence of SO_(2)-SO_(4)^(2−)conversion efficiency.Furthermore,the Pearson correlation analysis has been used to study the influence of NO_(2)/O_(3)on SO_(2)-SO_(4)^(2−)conversion,and the regional and seasonal differences have been analyzed by considering factors such as meteorology,pollution sources,and regional transport.Changes in the main components of secondary aerosols are closely linked with the co-control of regional PM_(2.5)and O_(3).Therefore,the exploration of the impact of co-existing NO_(2)/O_(3)gases on the secondary formation of sulfates in real atmosphere is significant.展开更多
The photochemical conversion of SO_(2) to sulfates on 4-(benzoyl)benzoic acid(4-BBA)was investigated deeply in the presence of anionic and cationic surfactants.The types of surfactants determined their effect behavior...The photochemical conversion of SO_(2) to sulfates on 4-(benzoyl)benzoic acid(4-BBA)was investigated deeply in the presence of anionic and cationic surfactants.The types of surfactants determined their effect behaviors,and cationic surfactants can significantly enhance the SO_(2) oxidation on 4-BBA under irradiation,as shown by larger SO_(2) uptake coefficients and sulfate production.Hydrophilic moieties in cationic surfactants have a greater enhancement effect on the photochemical conversion of SO_(2) to sulfates than the corresponding hydrophobic moieties.Cationic surfactants obviously increased the accumulation of H_(2)O on the surface,which was proved to be the main factor influencing the SO_(2) uptake and the sulfate formation on 4-BBA.SO_(2) lifetime and sulfate formation rate in the mixture system of photosensitive substances with surfactants were evaluated to be 2.25 days and 0.09μg/(m^(3)·h),respectively.展开更多
To evaluate the feasibility of recovering Pb and Zn sulfides and Ag-containing minerals from Zn leaching residue by the process of reduction roasting followed by flotation,the reaction behaviors of Pb and Zn sulfates ...To evaluate the feasibility of recovering Pb and Zn sulfides and Ag-containing minerals from Zn leaching residue by the process of reduction roasting followed by flotation,the reaction behaviors of Pb and Zn sulfates during this process were investigated.Chemical analysis showed that the transformation ratios of PbSO4 and ZnSO4 could reach 65.51%and 52.12%,respectively,after reduction roasting,and the introduction of a sulfidation agent could improve the transformation ratios of these sulfates.scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)revealed that temperature obviously affects the particle size,crystal growth,and morphology of the artificial Pb and Zn sulfide minerals.Particle size analysis demonstrated that the particle size of the materials increases after roasting.Flotation tests revealed that a flotation concentrate composed of 12.01wt%Pb,27.78wt%Zn,and 6.975×10^(−2)wt%Ag with recoveries of 60.54%,29.24%,and 57.64%,respectively,could be obtained after roasting.展开更多
Understanding the influence of sulfates over catalysts for selective catalytic reduction of NO with NH_(3)(NH_(3)-SCR)is crucial due to the universal presence of SO_(2)in exhaust gas.Depending on the degree of sulfati...Understanding the influence of sulfates over catalysts for selective catalytic reduction of NO with NH_(3)(NH_(3)-SCR)is crucial due to the universal presence of SO_(2)in exhaust gas.Depending on the degree of sulfation,there mainly exist surface and bulk sulfates and NH_(3)-SCR activity is generally considered to suffer more from bulk sulfates.Herein,the unique function of bulk sulfates over Ce O_(2)in promoting hightemperature SCR reaction is revealed.Notably,compared with CeO_(2)dominated with surface sulfates(S-CeO_(2)-4h)and commercial V_2O_5-WO_(3)/TiO_(2),CeO_(2)with bulk sulfates(S-Ce O_(2)-72h)exhibits admirable NO conversion at the temperature range of 400-550℃.Bulk sulfates provide more Br?nsted acid sites with stronger strength for NH_(3)adsorption.Moreover,the oxidation ability of Ce O_(2)is significantly inhibited due to electron-withdrawing effect from bulk sulfates,which alleviates NH_(3)oxidation at high temperatures.More NH_(3)adsorption with high stability and limited NH_(3)oxidation capacity ensure the excellent catalytic performance for S-CeO_(2)-72h in high-temperature denitration.This work provides new insight of bulk sulfates in promoting SCR activity and open a new avenue to design de NO_xcatalysts employed at high temperatures.展开更多
Herein,two antimony sulfates,named RbSb(SO_(4))_(2)(1)and CsSb(SO_(4))_(2)(2),have been successfully synthesized with the introduction of Sb^(3+)cation with stereochemically active lone pairs(SCALP)into sulfates by th...Herein,two antimony sulfates,named RbSb(SO_(4))_(2)(1)and CsSb(SO_(4))_(2)(2),have been successfully synthesized with the introduction of Sb^(3+)cation with stereochemically active lone pairs(SCALP)into sulfates by the conventional hydrothermal method.Both two compounds endow short ultraviolet(UV)absorption edges(281 nm and 278 nm,respectively)and large birefringence(0.171@546 nm and 0.174@546 nm,respectively),which means that they are promising short-wave UV optical materials.Interestingly,though both of the two compounds exhibit similar 1D chained structures,and possess the same functional moieties including SbO4 seesaws and SO4 tetrahedral groups,they exhibit significantly opposite macroscopic symmetries,i.e.,compound 1 crystallizes in a centrosymmetric(CS)manner(P2_(1)/n)and compound 2 in a noncentrosymmetric(NCS)manner(P2_(1)2_(1)2_(1)),due to the size of cations[r(Rb+)=1.56 A˚,r(Cs+)=1.67 A˚]affects the orientation of SCALP of the adjacent Sb^(3+).展开更多
The hygroscopicity and optical properties of alkylaminium sulfates （AASs） were investigated using a hygroscopicity tandem differential mobility analyzer coupled to a cavity ring-down spectrometer and a nephelometer....The hygroscopicity and optical properties of alkylaminium sulfates （AASs） were investigated using a hygroscopicity tandem differential mobility analyzer coupled to a cavity ring-down spectrometer and a nephelometer. AAS particles do not exhibit a deliquescence phenomenon and show a monotonic increase in diameter as the relative humidity （RH） ascends. Hygroscopic growth factors （GFs） for 40, 100 and 150 nm alkylaminium sulfate particles do not show an apparent Kelvin effect when RH is less than 45%, whereas GFs of the salt aerosols increase with initial particle size when RH is higher than 45%. Calculation using the Zdanovskii-Stokes-Robinson mixing rule suggests that hygroscopic growth of triethylaminium sulfate-ammonium sulfate mixtures is non-deliquescent, occurring at very low RH, implying that the displacement of ammonia by amine will significantly enhance the hygroscopicity of （NH4）2SO4 aerosols. In addition, light extinction of AAS particles is a combined effect of both scattering and absorption under dry conditions, but is dominated by scattering under wet conditions.展开更多
Neutral aqueous alkali sulfate has shown great interests for developing environmentally friendly high voltage and high energy supercapacitors. This work focuses on systematically investigating the properties of symmet...Neutral aqueous alkali sulfate has shown great interests for developing environmentally friendly high voltage and high energy supercapacitors. This work focuses on systematically investigating the properties of symmetric carbon/carbon supercapacitors in neutral aqueous alkali sulfates. At room temperature, the largest power and energy density were obtained with K2SO4 electrolyte due to the smallest cation dimensions and highest electrical conductivity. At low temperature, aqueous Li2SO4 electrolyte presents the best performance due to the largest solubility, allowing a long-term stability at temperatures ranging between 20℃ and –10℃ at a maximum voltage of 1.8 V. The excellent stability has been confirmed that capacitance retention achieves as high as 92% after 10,000 cycles. The capacitance variations with temperatures could essentially result from kinetic diffusion barrier, ion dimension changes and fewer pseudo-capacitance contributions under different temperatures. This work highlights the selected virtues of different alkali sulfate electrolytes for enhanced supercapacitors.展开更多
To explore the effects of ligustrazine on bone marrow heparan sulfates (HS) expression in bone marrow transplantation (BMT) mice, the syngeneic BMT mice were orally given 2 mg ligustrazine twice a day. On the 7th, 10t...To explore the effects of ligustrazine on bone marrow heparan sulfates (HS) expression in bone marrow transplantation (BMT) mice, the syngeneic BMT mice were orally given 2 mg ligustrazine twice a day. On the 7th, 10th, 14th, 18th day after BMT, peripheral blood cells and bone marrow nuclear cells (BMNC) were counted, and the expression levels of HS in bone marrow and on the stromal cell surfaces were detected by immunohistochemistry and flow cytometry assay respectively. In ligustrazine-treated group, the white blood cells (WBC) and BMNC on the 7th, 10th, 14th, 18th day and platelets (PLT) on the 7th, 10th day were all significantly more than those in control group (P<0.05). The bone marrow HS expression levels in ligustrazine-treated group were higher than those in control group (P<0.05) on the 7th, 10th, 14th, 18th day. However, the HS expression levels on the stromal cell surfaces showed no significant difference between the two groups on the 18th day (P>0.05). It was concluded that ligustrazine could up-regulate HS expression in bone marrow, which might be one of the mechanisms contributing to ligustrazine promoting hematopoietic reconstitution after BMT.展开更多
For the 2008 Olympic Games, drastic control measures were implemented on industrial and urban emissions of sulfur dioxide （SO2）, nitrogen oxides （NOx） and other pollutants to address the issues of poor air quality...For the 2008 Olympic Games, drastic control measures were implemented on industrial and urban emissions of sulfur dioxide （SO2）, nitrogen oxides （NOx） and other pollutants to address the issues of poor air quality in Beijing. To investigate the effects of SO2 and NOx reductions on the particulate sulfate and nitrate concentrations as well as their size distributions, size-segregated aerosol samples were collected using micro-orifice uniform deposit impactors （MOUDIs） at urban and downwind rural sites in Beijing before and after full-scale controls. During the sampling period, the mass concentrations of fine particles （PMI.s） at the urban and rural sites were 94.0 and 85.9 p.g m-3, respectively. More than 90% of the sulfates and 60% of nitrates formed as fine particles. Benefiting from the advantageous meteorological conditions and the source controls, sulfates were observed in rather low concentrations and primarily in condensation mode during the Olympics. The effects of the control measures were separately analyzed for the northerly and the southerly air-mass-dominated days to account for any bias. After the control measures were implemented, PM, sulfates, and nitrates were significantly reduced when the northerly air masses prevailed, with a higher percentage of reduction in larger particles. The droplet mode particles, which dominated the sulfates and nitrates before the controls were implemented, were remarkably reduced in mass concentration after the control measures were implemented. Nevertheless, when the polluted southerly air masses prevailed, the local source control measures in Beijing did not effectively reduce the ambient sulfate concentration due to the enormous regional contribution from the North China Plain.展开更多
Numerous light rare earth elements(LREE)minerals containing Fe and P were processed by sulfuric acid roasting method,and the leaching solution mainly comprises LREE sulfate,Fe2(SO4)3,H3PO4,and H2SO4,however,the solubi...Numerous light rare earth elements(LREE)minerals containing Fe and P were processed by sulfuric acid roasting method,and the leaching solution mainly comprises LREE sulfate,Fe2(SO4)3,H3PO4,and H2SO4,however,the solubility data of LREE sulfates in this system is few.This work studies the solubility of LREE sulfates in independent LREE sulfate system RE2(SO4)3-Fe2(SO4)3-H3 PO4-H2SO4(RE=La,Ce,Pr or Nd)and mixed LREE sulfates system(La,Ce,Pr,Nd)2(SO4)3-Fe2(SO4)3-H3 PO4-H2SO4 at different temperature(25-65℃)and concentrations of Fe2(SO4)3(Fe2 O3,0-50.13 g/L),H2SO4(0.5 mol/L),and H3 PO4(P2 O5,20.34 g/L)based on the industrial operating condition at low liquid and solid ratio 2:1.The solubility of each LREE sulfate in the independent system(La2 O3,12.25-20.88 g/L;CeO2,41.93-62.35 g/L;Pr6 O11,37.34-56.69 g/L;Nd2 O3,26.60-37.63 g/L)is much higher than that of the mixed system(La2 O3,6.95-11.03 g/L;CeO2,10.63-21.51 g/L;Pr6 O11,11.56-20.36 g/L;Nd2 O3,12.36-19.79 g/L)under the same other conditions.The results also indicate that,in the two systems,both Fe and the temperature have negative effects on the solubility of LREE sulfates.That may occur due to the complication reactions between the complexes of RESO4+and Fe(SO4)2-.However,the influence degree of temperature and iron concentration on the LREE sulfates solubility varies in the two systems and among different LREE species.This research is of theoretical significance for optimizing the conditions of the sulfuric acid process for recovering the LREE from the mixed LREE bearing minerals as well as the single LREE containing secondary rare earth scraps.展开更多
Seven new rare earth transition metal sulfates were synthesized by hydrothermal reactions under conditions slightly above the critical point of water. Their crystal structures were determined from single crystal X-ray...Seven new rare earth transition metal sulfates were synthesized by hydrothermal reactions under conditions slightly above the critical point of water. Their crystal structures were determined from single crystal X-ray data. The compositions of the new compounds can be represented by two general formulae ： REM （OH） 3 （SO4） and RE2M （OH） 3 （SO4） 2F （H2O） with RE = Gd, Tb, Dy ; M = Ni, Cu. Three different crystal structure types were found for the formula REM （OH） 3 （SO4）. The structures of the new compounds all feature infinite chains of REOn coordination polyhedra, which are connected to chains of CuO6 or NiO6 octabedra. The limited size range of the rare earth cations observed in these compounds is most likely because of interactions between the octabedral chains and the chains of REOn polyhedra. The new compounds are closely related to the known yttrium transition metal sulfates.展开更多
The kinetic characteristics of alkenes involved in thermochemical sulfate reduction (TSR) have been never reported in geological literature. In this study, TSR by ethene under hydrothermal conditions was performed in ...The kinetic characteristics of alkenes involved in thermochemical sulfate reduction (TSR) have been never reported in geological literature. In this study, TSR by ethene under hydrothermal conditions was performed in the constrained simulation experiments. Typical TSR products consisted of H<sub>2</sub>S, CO<sub>2</sub>, mercaptans, sulfides, thiophenes derivatives and benzothiophene. The apparent activation energy E and apparent frequency factor A for TSR by ethene were determined as 76.370 kJ/mol and 4.579 s<sup>-1</sup>, respectively. The lower activation energy for ethene involved in TSR relative to ethane suggested that the reactivity of ethene is much higher than that of ethane, in accordance with the thermodynamic analysis. Rate constants were determined experimentally using first-order kinetics extrapolate to MgSO<sub>4</sub> half-lives of 67.329 years - 3.053 years in deep burial diagenetic settings (120°C - 180°C). These values demonstrate that the reaction rate for TSR by ethene is extraordinarily fast in high-temperature gas reservoirs (120°C - 180°C). Consequently, the newly formed ethene from thermal cracking and TSR alteration of natural gas and/or petroleum could not survive after TSR process and were rarely detected in natural TSR reservoirs.展开更多
Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high...Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high condensate content,high temperature,and high salinity)often affect foaming agent performance.In this study,surfactants were screened using an airflow method that closely resembles field treatment method.Notably,alcohol ether sulfates(AE_(n)S)with various polyoxyethylene(EO)units demonstrated exceptional performance in terms of liquid unloading efficiency and foam stability.At 80℃,the unloading efficiency of AE_(n)S with two EO units(AE_(2)S)in a high NaCl mass concentration(up to 200 g/L)and high condensate volume fraction(up to 20%)reached 84%.The dynamic surface tension and interfacial tension measured at the same temperature were used to analyze the influence of the diffusion rate and interfacial characteristics on the AE_(n)S foam,while the viscosity and liquid film thickness measurements reflected the mechanical strength and liquid-carrying capacity.In addition,transmission electron microscopy(TEM)revealed that AE_(2)S formed“dendritic”micellar aggregates at a high NaCl mass concentration,which significantly enhanced the viscosity and stability of the foam.The interactions among AE_(n)S,NaCl,and H2O were analyzed using molecular dynamics,and it was confirmed from a molecular mechanics perspective that a stable structure can form among the three,contributing to the foam stability.These findings demonstrate the significant potential of the AE_(2)S foam for gas well deliquification.展开更多
Sulfate minerals are widely distributed across various geological settings on Earth and provide critical insights into a range of geochemical processes and environmental evolution.Both modern and ancient sulfates poss...Sulfate minerals are widely distributed across various geological settings on Earth and provide critical insights into a range of geochemical processes and environmental evolution.Both modern and ancient sulfates possess exceptional potential for preserving biosignatures.Recent studies utilizing remote sensing and in situ exploration techniques have identified extensive sulfate-bearing deposits on the Martian surface.Investigating the habitability and the potential for biosignature preservation in these regions is a key focus in the search for life on Mars.Therefore,this review synthesizes the types,distribution,and formation environments of terrestrial sulfate minerals and summarizes the occurrence and preservation characteristics of biosignatures within both modern and ancient terrestrial sulfates.In light of the current understanding of the occurrence of Martian sulfates,the study further explores the potential for biosignature preservation within Martian sulfate deposits.Finally,drawing on results from current in situ life-detection missions and the objectives of forthcoming Mars sample return missions,this paper provides scientific recommendations for biosignature detection strategies and landing site selection in future Mars exploration missions.展开更多
Deep-ultraviolet(deep-UV)nonlinear optical(NLO)crystals are of current interest because they play an indis-pensable role in modern scientific equipment.Searching these crystals was traditionally limited toπ-conjugate...Deep-ultraviolet(deep-UV)nonlinear optical(NLO)crystals are of current interest because they play an indis-pensable role in modern scientific equipment.Searching these crystals was traditionally limited toπ-conjugated systems,such as borates and carbonates.In 2019,our group reported two non-π-conjugated sulfates as new sources of deep-UV NLO crystals for the first time.In this mini review,we provide a comprehensive overview of the recent development of non-π-conjugated NLO sulfates with deep-UV absorption edge in aspect of synthesis methods,crystal structures,thermal stability,and optical performance.Besides,we conclude the crucial structure-property relationships,and further give some prospects for exploring non-π-conjugated NLO sulfates with deep-UV absorption edge with high thermal stability,enhanced second-order NLO effects,birefringence,etc.We believe that this mini review will not only facilitate researchers to design superior non-π-conjugated NLO sulfates with deep-UV absorption edge but also shed useful insights on the explorations of other non-π-conjugated deep-UV NLO crystal systems.展开更多
Spinal cord injuries have overwhelming physical and occupational implications for patients.Moreover,the extensive and long-term medical care required for spinal cord injury significantly increases healthcare costs and...Spinal cord injuries have overwhelming physical and occupational implications for patients.Moreover,the extensive and long-term medical care required for spinal cord injury significantly increases healthcare costs and resources,adding a substantial burden to the healthcare system and patients'families.In this context,chondroitinase ABC,a bacterial enzyme isolated from Proteus vulgaris that is modified to facilitate expression and secretion in mammals,has emerged as a promising therapeutic agent.It works by degrading chondroitin sulfate proteoglycans,cleaving the glycosaminoglycanchains of chondroitin sulfate proteoglycans into soluble disaccharides or tetrasaccharides.Chondroitin sulfate proteoglycans are potent axon growth inhibitors and principal constituents of the extracellular matrix surrounding glial and neuronal cells attached to glycosaminoglycan chains.Chondroitinase ABC has been shown to play an effective role in promoting recovery from acute and chronic spinal cord injury by improving axonal regeneration and sprouting,enhancing the plasticity of perineuronal nets,inhibiting neuronal apoptosis,and modulating immune responses in various animal models.In this review,we introduce the classification and pathological mechanisms of spinal cord injury and discuss the pathophysiological role of chondroitin sulfate proteoglycans in spinal cord injury.We also highlight research advancements in spinal cord injury treatment strategies,with a focus on chondroitinase ABC,and illustrate how improvements in chondroitinase ABC stability,enzymatic activity,and delivery methods have enhanced injured spinal cord repair.Furthermore,we emphasize that combination treatment with chondroitinase ABC further enhances therapeutic efficacy.This review aimed to provide a comprehensive understanding of the current trends and future directions of chondroitinase ABC-based spinal cord injury therapies,with an emphasis on how modern technologies are accelerating the optimization of chondroitinase ABC development.展开更多
A zinc sulfate open framework matrix,[Zn(SO_4)(DMSO)](1),was synthesized by solvothermal evaporationusing dimethyl sulfoxide(DMSO)as the solvent.A compositeP@1,which exhibits fluorescence and room tempera-ture phospho...A zinc sulfate open framework matrix,[Zn(SO_4)(DMSO)](1),was synthesized by solvothermal evaporationusing dimethyl sulfoxide(DMSO)as the solvent.A compositeP@1,which exhibits fluorescence and room tempera-ture phosphorescence(RTP)properties,was prepared by doping 2,6-naphthalic acid(P)into matrix1at a low con-centration.P@1emitted a green RTP that was visible to the naked eye and lasted for approximately 2 s.P@1exhib-ited selective phosphorescence enhancement response towards Pb^(2+),with a detection limit of 2.52μmol·L^(-1).Themain detection mechanism is the Pb—O coordination-induced phosphorescence enhancement in the system.Inter-estingly,P@1also functioned as a dual-channel probe for the rapid detection of Fe^(3+)ions through fluorescencequenching with a detection limit of 0.038μmol·L^(-1).The recognition mechanism may be attributed to the competi-tive energy absorption betweenP@1and Fe^(3+)ions.CCDC:2388502,1.展开更多
The leaching of sulfuric acid converted product of scheelite in NH_(3)·H_(2)O−NH_(4)HCO_(3)solution was systemically studied to improve sulfuric acid conversion−ammonium salts leaching technology route for ammoni...The leaching of sulfuric acid converted product of scheelite in NH_(3)·H_(2)O−NH_(4)HCO_(3)solution was systemically studied to improve sulfuric acid conversion−ammonium salts leaching technology route for ammonium paratungstate production.The results showed that the WO_(3)leaching efficiency was about 99%under optimal conditions of 350 r/min,liquid-to-solid ratio of 3 mL/g,1 mol/L NH_(4)HCO_(3),4 mol/L NH_(3)·H_(2)O,25℃,and 15 min.During the leaching,CaSO_(4)almost had no change and was still in a banding or rod-like shape in short leaching time,while conglobate CaCO_(3)was gradually formed on the CaSO_(4)surface.A secondary reaction might occur between CaSO_(4)and WO_(4)^(2−),which could be restrained by a certain amount of CO_(3)^(2−)in the solution.There was no CaCO_(3)phase determined by XRD in leaching residue of converted product for scheelite concentrate under optimal conditions,which was different from that for synthetic scheelite.The leaching process could be explained by neutralization reaction of H_(2)WO_(4)and solid transformation of CaSO_(4)in NH_(3)·H_(2)O−NH_(4)HCO_(3)solution.展开更多
Scientific knowledge on the chemical compositions of fine particulate matter(PM_(2.5)) is essential for properly assessing its health and climate effects,and for decisionmakers to develop efficient mitigation strategi...Scientific knowledge on the chemical compositions of fine particulate matter(PM_(2.5)) is essential for properly assessing its health and climate effects,and for decisionmakers to develop efficient mitigation strategies.A high-resolution PM_(2.5) chemical composition dataset(CAQRA-aerosol)is developed in this study,which provides hourly maps of organic carbon,black carbon,ammonium,nitrate,and sulfate in China from 2013 to 2020 with a horizontal resolution of 15 km.This paper describes the method,access,and validation results of this dataset.It shows that CAQRA-aerosol has good consistency with observations and achieves higher or comparable accuracy with previous PM_(2.5) composition datasets.Based on CAQRA-aerosol,spatiotemporal changes of different PM_(2.5) compositions were investigated from a national viewpoint,which emphasizes different changes of nitrate from other compositions.The estimated annual rate of population-weighted concentrations of nitrate is 0.23μg m^(−3)yr^(−1) from 2015 to 2020,compared with−0.19 to−1.1μg m^(−3)yr^(−1) for other compositions.The whole dataset is freely available from the China Air Pollution Data Center(https://doi.org/10.12423/capdb_PKU.2023.DA).展开更多
The progressive failure characteristics of geomaterial are a remarkable and challenging topic in geotechnical engineering.To study the effect of salt content and temperature on the progressive failure characteristics ...The progressive failure characteristics of geomaterial are a remarkable and challenging topic in geotechnical engineering.To study the effect of salt content and temperature on the progressive failure characteristics of frozen sodium sulfate saline sandy soil,a series of uniaxial compression tests were performed by integrating digital image correlation(DIC)technology into the testing apparatus.The evolution law of the uniaxial compression strength(UCS),the failure strain,and the formation of the shear band of the frozen sodium sulfate saline sandy soil were analyzed.The test results show that within the scope of this study,with the increase of salt content,both the UCS and the shear band angle initially decrease with increasing salt content before showing an increase.In contrast,the failure strain and the width of the shear band exhibit an initial increase followed by a decrease in the samples.In addition,to investigate the brittle failure characteristics of frozen sodium sulfate saline sandy soil,two classic brittleness evaluation methods were employed to quantitatively assess the brittleness level for the soil samples.The findings suggest that the failure characteristics under all test conditions in this study belong to the transition stage between brittle and ductile,indicating that frozen sodium sulfate saline sandy soil exhibits certain brittle behavior under uniaxial compression conditions,and the brittleness index basically decreases and then increases with the rise in salt content.展开更多
基金supported by the National Natural Science Foundation of China(No.52160024)the Natural Science Foundation of Hunan Province,China(No.2022JJ30475)+2 种基金the Innovation Team Funds of China West Normal University(No.KCXTD2023-4)the Natural Science Foundation of Sichuan,China(No.24NSFSC0537)the Fundamental Research Funds of China West Normal University(Nos.22kE015 and 22kE016).
文摘As an important component of secondary aerosols,sulfate plays a crucial role in regulating atmospheric radiative balance and influencing the secondary formation of ozone(O_(3)).In real atmosphere,atmospheric oxidants NO_(2)and O_(3)can promote the oxidation of SO_(2)to form sulfate(SO_(4)^(2−))through multiphase chemistry that occur at different time scales.Due to the combined impact of meteorology,pollution sources,atmospheric chemistry,etc.,time-scale dependence of SO_(2)-SO_(4)^(2−)conversion makes the impact of NO_(2)/O_(3)on it more complex.In this study,based on long-term time series(2013-2020)of air pollution variables from seven stations in Hong Kong,the Multifractal Detrended Cross-Correlation Analysis(MFDCCA)method has been employed to quantify the cross-correlations between SO_(2)and SO_(4)^(2−)in real atmosphere at different time scales,for examining the time-scale dependence of SO_(2)-SO_(4)^(2−)conversion efficiency.Furthermore,the Pearson correlation analysis has been used to study the influence of NO_(2)/O_(3)on SO_(2)-SO_(4)^(2−)conversion,and the regional and seasonal differences have been analyzed by considering factors such as meteorology,pollution sources,and regional transport.Changes in the main components of secondary aerosols are closely linked with the co-control of regional PM_(2.5)and O_(3).Therefore,the exploration of the impact of co-existing NO_(2)/O_(3)gases on the secondary formation of sulfates in real atmosphere is significant.
基金supported by the National Natural Science Foundation of China(Nos.42077198 and 22206023)Liaoning Revitalization Talents Program(No.XLYC1907185)+1 种基金Liaoning Science and Technology Joint Project(No.2023-MSBA-109)the Fundamental Research Funds for the Central Universities(Nos.N2325019 and N2325034).
文摘The photochemical conversion of SO_(2) to sulfates on 4-(benzoyl)benzoic acid(4-BBA)was investigated deeply in the presence of anionic and cationic surfactants.The types of surfactants determined their effect behaviors,and cationic surfactants can significantly enhance the SO_(2) oxidation on 4-BBA under irradiation,as shown by larger SO_(2) uptake coefficients and sulfate production.Hydrophilic moieties in cationic surfactants have a greater enhancement effect on the photochemical conversion of SO_(2) to sulfates than the corresponding hydrophobic moieties.Cationic surfactants obviously increased the accumulation of H_(2)O on the surface,which was proved to be the main factor influencing the SO_(2) uptake and the sulfate formation on 4-BBA.SO_(2) lifetime and sulfate formation rate in the mixture system of photosensitive substances with surfactants were evaluated to be 2.25 days and 0.09μg/(m^(3)·h),respectively.
基金the National Natural Science Foundation of China(No.51964027)the Yunnan Province Applied Basic Research Project,China(No.2017FB084)+1 种基金the Foundation of Yunnan’s Education Ministry,China(No.2019J0037)the Testing and Analyzing Funds of Kunming University of Science and Technology(No.2018T20150055).
文摘To evaluate the feasibility of recovering Pb and Zn sulfides and Ag-containing minerals from Zn leaching residue by the process of reduction roasting followed by flotation,the reaction behaviors of Pb and Zn sulfates during this process were investigated.Chemical analysis showed that the transformation ratios of PbSO4 and ZnSO4 could reach 65.51%and 52.12%,respectively,after reduction roasting,and the introduction of a sulfidation agent could improve the transformation ratios of these sulfates.scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)revealed that temperature obviously affects the particle size,crystal growth,and morphology of the artificial Pb and Zn sulfide minerals.Particle size analysis demonstrated that the particle size of the materials increases after roasting.Flotation tests revealed that a flotation concentrate composed of 12.01wt%Pb,27.78wt%Zn,and 6.975×10^(−2)wt%Ag with recoveries of 60.54%,29.24%,and 57.64%,respectively,could be obtained after roasting.
基金The financial supports from the National Natural Science Foundation of China(Nos.21976081,21972062)Major Scientific and Technological Project of Bingtuan(No.2018AA002),are greatly acknowledged。
文摘Understanding the influence of sulfates over catalysts for selective catalytic reduction of NO with NH_(3)(NH_(3)-SCR)is crucial due to the universal presence of SO_(2)in exhaust gas.Depending on the degree of sulfation,there mainly exist surface and bulk sulfates and NH_(3)-SCR activity is generally considered to suffer more from bulk sulfates.Herein,the unique function of bulk sulfates over Ce O_(2)in promoting hightemperature SCR reaction is revealed.Notably,compared with CeO_(2)dominated with surface sulfates(S-CeO_(2)-4h)and commercial V_2O_5-WO_(3)/TiO_(2),CeO_(2)with bulk sulfates(S-Ce O_(2)-72h)exhibits admirable NO conversion at the temperature range of 400-550℃.Bulk sulfates provide more Br?nsted acid sites with stronger strength for NH_(3)adsorption.Moreover,the oxidation ability of Ce O_(2)is significantly inhibited due to electron-withdrawing effect from bulk sulfates,which alleviates NH_(3)oxidation at high temperatures.More NH_(3)adsorption with high stability and limited NH_(3)oxidation capacity ensure the excellent catalytic performance for S-CeO_(2)-72h in high-temperature denitration.This work provides new insight of bulk sulfates in promoting SCR activity and open a new avenue to design de NO_xcatalysts employed at high temperatures.
基金the National Natural Science Foundation of China(Nos.22122106,22071158,21971171)the Fundamental Research Funds from Sichuan University(No.2021SCUNL101).
文摘Herein,two antimony sulfates,named RbSb(SO_(4))_(2)(1)and CsSb(SO_(4))_(2)(2),have been successfully synthesized with the introduction of Sb^(3+)cation with stereochemically active lone pairs(SCALP)into sulfates by the conventional hydrothermal method.Both two compounds endow short ultraviolet(UV)absorption edges(281 nm and 278 nm,respectively)and large birefringence(0.171@546 nm and 0.174@546 nm,respectively),which means that they are promising short-wave UV optical materials.Interestingly,though both of the two compounds exhibit similar 1D chained structures,and possess the same functional moieties including SbO4 seesaws and SO4 tetrahedral groups,they exhibit significantly opposite macroscopic symmetries,i.e.,compound 1 crystallizes in a centrosymmetric(CS)manner(P2_(1)/n)and compound 2 in a noncentrosymmetric(NCS)manner(P2_(1)2_(1)2_(1)),due to the size of cations[r(Rb+)=1.56 A˚,r(Cs+)=1.67 A˚]affects the orientation of SCALP of the adjacent Sb^(3+).
基金supported by the National Natural Science Foundation of China(Nos.21190053,21177025,20937001)the Shanghai Science and Technology Commission of Shanghai Municipality(No.12DJ1400100,13XD1400700)+2 种基金the Priority Fields for Ph.D.Programs Foundation of Ministry of Education of China(No.20110071130003)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB05010200)FP7 Project(AMIS)(No.PIRSES-GA-2011)
文摘The hygroscopicity and optical properties of alkylaminium sulfates （AASs） were investigated using a hygroscopicity tandem differential mobility analyzer coupled to a cavity ring-down spectrometer and a nephelometer. AAS particles do not exhibit a deliquescence phenomenon and show a monotonic increase in diameter as the relative humidity （RH） ascends. Hygroscopic growth factors （GFs） for 40, 100 and 150 nm alkylaminium sulfate particles do not show an apparent Kelvin effect when RH is less than 45%, whereas GFs of the salt aerosols increase with initial particle size when RH is higher than 45%. Calculation using the Zdanovskii-Stokes-Robinson mixing rule suggests that hygroscopic growth of triethylaminium sulfate-ammonium sulfate mixtures is non-deliquescent, occurring at very low RH, implying that the displacement of ammonia by amine will significantly enhance the hygroscopicity of （NH4）2SO4 aerosols. In addition, light extinction of AAS particles is a combined effect of both scattering and absorption under dry conditions, but is dominated by scattering under wet conditions.
基金supported as part of the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy,Office of Science,Office of Basic Energy Sciences
文摘Neutral aqueous alkali sulfate has shown great interests for developing environmentally friendly high voltage and high energy supercapacitors. This work focuses on systematically investigating the properties of symmetric carbon/carbon supercapacitors in neutral aqueous alkali sulfates. At room temperature, the largest power and energy density were obtained with K2SO4 electrolyte due to the smallest cation dimensions and highest electrical conductivity. At low temperature, aqueous Li2SO4 electrolyte presents the best performance due to the largest solubility, allowing a long-term stability at temperatures ranging between 20℃ and –10℃ at a maximum voltage of 1.8 V. The excellent stability has been confirmed that capacitance retention achieves as high as 92% after 10,000 cycles. The capacitance variations with temperatures could essentially result from kinetic diffusion barrier, ion dimension changes and fewer pseudo-capacitance contributions under different temperatures. This work highlights the selected virtues of different alkali sulfate electrolytes for enhanced supercapacitors.
基金This project was supported by a grant from National Natu-ral Sciences Foundation of China( No. 3 9870 92 6)
文摘To explore the effects of ligustrazine on bone marrow heparan sulfates (HS) expression in bone marrow transplantation (BMT) mice, the syngeneic BMT mice were orally given 2 mg ligustrazine twice a day. On the 7th, 10th, 14th, 18th day after BMT, peripheral blood cells and bone marrow nuclear cells (BMNC) were counted, and the expression levels of HS in bone marrow and on the stromal cell surfaces were detected by immunohistochemistry and flow cytometry assay respectively. In ligustrazine-treated group, the white blood cells (WBC) and BMNC on the 7th, 10th, 14th, 18th day and platelets (PLT) on the 7th, 10th day were all significantly more than those in control group (P<0.05). The bone marrow HS expression levels in ligustrazine-treated group were higher than those in control group (P<0.05) on the 7th, 10th, 14th, 18th day. However, the HS expression levels on the stromal cell surfaces showed no significant difference between the two groups on the 18th day (P>0.05). It was concluded that ligustrazine could up-regulate HS expression in bone marrow, which might be one of the mechanisms contributing to ligustrazine promoting hematopoietic reconstitution after BMT.
基金the National Key Basic Research Program of China (973program)，a key project of the Shandong Provincial Environmental Protection Department，the Niche Area Development Scheme of the Hong Kong Polytechnic University，the Hong Kong Research Grants Council，the central level,scientific research institutes for basic R & D special fund business
文摘For the 2008 Olympic Games, drastic control measures were implemented on industrial and urban emissions of sulfur dioxide （SO2）, nitrogen oxides （NOx） and other pollutants to address the issues of poor air quality in Beijing. To investigate the effects of SO2 and NOx reductions on the particulate sulfate and nitrate concentrations as well as their size distributions, size-segregated aerosol samples were collected using micro-orifice uniform deposit impactors （MOUDIs） at urban and downwind rural sites in Beijing before and after full-scale controls. During the sampling period, the mass concentrations of fine particles （PMI.s） at the urban and rural sites were 94.0 and 85.9 p.g m-3, respectively. More than 90% of the sulfates and 60% of nitrates formed as fine particles. Benefiting from the advantageous meteorological conditions and the source controls, sulfates were observed in rather low concentrations and primarily in condensation mode during the Olympics. The effects of the control measures were separately analyzed for the northerly and the southerly air-mass-dominated days to account for any bias. After the control measures were implemented, PM, sulfates, and nitrates were significantly reduced when the northerly air masses prevailed, with a higher percentage of reduction in larger particles. The droplet mode particles, which dominated the sulfates and nitrates before the controls were implemented, were remarkably reduced in mass concentration after the control measures were implemented. Nevertheless, when the polluted southerly air masses prevailed, the local source control measures in Beijing did not effectively reduce the ambient sulfate concentration due to the enormous regional contribution from the North China Plain.
基金Project supported by the National Natural Science Foundation of China(51674037)GRINM Youth Foundation。
文摘Numerous light rare earth elements(LREE)minerals containing Fe and P were processed by sulfuric acid roasting method,and the leaching solution mainly comprises LREE sulfate,Fe2(SO4)3,H3PO4,and H2SO4,however,the solubility data of LREE sulfates in this system is few.This work studies the solubility of LREE sulfates in independent LREE sulfate system RE2(SO4)3-Fe2(SO4)3-H3 PO4-H2SO4(RE=La,Ce,Pr or Nd)and mixed LREE sulfates system(La,Ce,Pr,Nd)2(SO4)3-Fe2(SO4)3-H3 PO4-H2SO4 at different temperature(25-65℃)and concentrations of Fe2(SO4)3(Fe2 O3,0-50.13 g/L),H2SO4(0.5 mol/L),and H3 PO4(P2 O5,20.34 g/L)based on the industrial operating condition at low liquid and solid ratio 2:1.The solubility of each LREE sulfate in the independent system(La2 O3,12.25-20.88 g/L;CeO2,41.93-62.35 g/L;Pr6 O11,37.34-56.69 g/L;Nd2 O3,26.60-37.63 g/L)is much higher than that of the mixed system(La2 O3,6.95-11.03 g/L;CeO2,10.63-21.51 g/L;Pr6 O11,11.56-20.36 g/L;Nd2 O3,12.36-19.79 g/L)under the same other conditions.The results also indicate that,in the two systems,both Fe and the temperature have negative effects on the solubility of LREE sulfates.That may occur due to the complication reactions between the complexes of RESO4+and Fe(SO4)2-.However,the influence degree of temperature and iron concentration on the LREE sulfates solubility varies in the two systems and among different LREE species.This research is of theoretical significance for optimizing the conditions of the sulfuric acid process for recovering the LREE from the mixed LREE bearing minerals as well as the single LREE containing secondary rare earth scraps.
基金Foundation ite m:Project supported by R.A.Welch Foundation
文摘Seven new rare earth transition metal sulfates were synthesized by hydrothermal reactions under conditions slightly above the critical point of water. Their crystal structures were determined from single crystal X-ray data. The compositions of the new compounds can be represented by two general formulae ： REM （OH） 3 （SO4） and RE2M （OH） 3 （SO4） 2F （H2O） with RE = Gd, Tb, Dy ; M = Ni, Cu. Three different crystal structure types were found for the formula REM （OH） 3 （SO4）. The structures of the new compounds all feature infinite chains of REOn coordination polyhedra, which are connected to chains of CuO6 or NiO6 octabedra. The limited size range of the rare earth cations observed in these compounds is most likely because of interactions between the octabedral chains and the chains of REOn polyhedra. The new compounds are closely related to the known yttrium transition metal sulfates.
文摘The kinetic characteristics of alkenes involved in thermochemical sulfate reduction (TSR) have been never reported in geological literature. In this study, TSR by ethene under hydrothermal conditions was performed in the constrained simulation experiments. Typical TSR products consisted of H<sub>2</sub>S, CO<sub>2</sub>, mercaptans, sulfides, thiophenes derivatives and benzothiophene. The apparent activation energy E and apparent frequency factor A for TSR by ethene were determined as 76.370 kJ/mol and 4.579 s<sup>-1</sup>, respectively. The lower activation energy for ethene involved in TSR relative to ethane suggested that the reactivity of ethene is much higher than that of ethane, in accordance with the thermodynamic analysis. Rate constants were determined experimentally using first-order kinetics extrapolate to MgSO<sub>4</sub> half-lives of 67.329 years - 3.053 years in deep burial diagenetic settings (120°C - 180°C). These values demonstrate that the reaction rate for TSR by ethene is extraordinarily fast in high-temperature gas reservoirs (120°C - 180°C). Consequently, the newly formed ethene from thermal cracking and TSR alteration of natural gas and/or petroleum could not survive after TSR process and were rarely detected in natural TSR reservoirs.
文摘Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high condensate content,high temperature,and high salinity)often affect foaming agent performance.In this study,surfactants were screened using an airflow method that closely resembles field treatment method.Notably,alcohol ether sulfates(AE_(n)S)with various polyoxyethylene(EO)units demonstrated exceptional performance in terms of liquid unloading efficiency and foam stability.At 80℃,the unloading efficiency of AE_(n)S with two EO units(AE_(2)S)in a high NaCl mass concentration(up to 200 g/L)and high condensate volume fraction(up to 20%)reached 84%.The dynamic surface tension and interfacial tension measured at the same temperature were used to analyze the influence of the diffusion rate and interfacial characteristics on the AE_(n)S foam,while the viscosity and liquid film thickness measurements reflected the mechanical strength and liquid-carrying capacity.In addition,transmission electron microscopy(TEM)revealed that AE_(2)S formed“dendritic”micellar aggregates at a high NaCl mass concentration,which significantly enhanced the viscosity and stability of the foam.The interactions among AE_(n)S,NaCl,and H2O were analyzed using molecular dynamics,and it was confirmed from a molecular mechanics perspective that a stable structure can form among the three,contributing to the foam stability.These findings demonstrate the significant potential of the AE_(2)S foam for gas well deliquification.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0504000)the National Natural Science Foundation of China(Grant No.42272274)+2 种基金the National Key Research and Development Program of China(Grant No.2021YFA0716100)the Natural Science Foundation of Hubei Province(Grant No.2024AFB692)the Macao Science and Technology Development Fund(FDCT)(Grant No.0052/2024/RIA1)。
文摘Sulfate minerals are widely distributed across various geological settings on Earth and provide critical insights into a range of geochemical processes and environmental evolution.Both modern and ancient sulfates possess exceptional potential for preserving biosignatures.Recent studies utilizing remote sensing and in situ exploration techniques have identified extensive sulfate-bearing deposits on the Martian surface.Investigating the habitability and the potential for biosignature preservation in these regions is a key focus in the search for life on Mars.Therefore,this review synthesizes the types,distribution,and formation environments of terrestrial sulfate minerals and summarizes the occurrence and preservation characteristics of biosignatures within both modern and ancient terrestrial sulfates.In light of the current understanding of the occurrence of Martian sulfates,the study further explores the potential for biosignature preservation within Martian sulfate deposits.Finally,drawing on results from current in situ life-detection missions and the objectives of forthcoming Mars sample return missions,this paper provides scientific recommendations for biosignature detection strategies and landing site selection in future Mars exploration missions.
基金the National Natural Science Foundation of China(22122507,22193042,21833010,61975207,and 21921001)the Natural Science Foundation of Fujian Province(2022J02012)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y202069)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LY-SLH024)Fujian Institute of Innovation(FJCXY18010201)in Chinese Academy of Sciences.
文摘Deep-ultraviolet(deep-UV)nonlinear optical(NLO)crystals are of current interest because they play an indis-pensable role in modern scientific equipment.Searching these crystals was traditionally limited toπ-conjugated systems,such as borates and carbonates.In 2019,our group reported two non-π-conjugated sulfates as new sources of deep-UV NLO crystals for the first time.In this mini review,we provide a comprehensive overview of the recent development of non-π-conjugated NLO sulfates with deep-UV absorption edge in aspect of synthesis methods,crystal structures,thermal stability,and optical performance.Besides,we conclude the crucial structure-property relationships,and further give some prospects for exploring non-π-conjugated NLO sulfates with deep-UV absorption edge with high thermal stability,enhanced second-order NLO effects,birefringence,etc.We believe that this mini review will not only facilitate researchers to design superior non-π-conjugated NLO sulfates with deep-UV absorption edge but also shed useful insights on the explorations of other non-π-conjugated deep-UV NLO crystal systems.
基金supported by the National Natural Science Foundation of China,No.82002645China Postdoctoral Science Foundation,No.2022M722321Jiangsu Funding Program for Excellent Postdoctoral Talent,No.2022ZB552(all to YH)。
文摘Spinal cord injuries have overwhelming physical and occupational implications for patients.Moreover,the extensive and long-term medical care required for spinal cord injury significantly increases healthcare costs and resources,adding a substantial burden to the healthcare system and patients'families.In this context,chondroitinase ABC,a bacterial enzyme isolated from Proteus vulgaris that is modified to facilitate expression and secretion in mammals,has emerged as a promising therapeutic agent.It works by degrading chondroitin sulfate proteoglycans,cleaving the glycosaminoglycanchains of chondroitin sulfate proteoglycans into soluble disaccharides or tetrasaccharides.Chondroitin sulfate proteoglycans are potent axon growth inhibitors and principal constituents of the extracellular matrix surrounding glial and neuronal cells attached to glycosaminoglycan chains.Chondroitinase ABC has been shown to play an effective role in promoting recovery from acute and chronic spinal cord injury by improving axonal regeneration and sprouting,enhancing the plasticity of perineuronal nets,inhibiting neuronal apoptosis,and modulating immune responses in various animal models.In this review,we introduce the classification and pathological mechanisms of spinal cord injury and discuss the pathophysiological role of chondroitin sulfate proteoglycans in spinal cord injury.We also highlight research advancements in spinal cord injury treatment strategies,with a focus on chondroitinase ABC,and illustrate how improvements in chondroitinase ABC stability,enzymatic activity,and delivery methods have enhanced injured spinal cord repair.Furthermore,we emphasize that combination treatment with chondroitinase ABC further enhances therapeutic efficacy.This review aimed to provide a comprehensive understanding of the current trends and future directions of chondroitinase ABC-based spinal cord injury therapies,with an emphasis on how modern technologies are accelerating the optimization of chondroitinase ABC development.
文摘A zinc sulfate open framework matrix,[Zn(SO_4)(DMSO)](1),was synthesized by solvothermal evaporationusing dimethyl sulfoxide(DMSO)as the solvent.A compositeP@1,which exhibits fluorescence and room tempera-ture phosphorescence(RTP)properties,was prepared by doping 2,6-naphthalic acid(P)into matrix1at a low con-centration.P@1emitted a green RTP that was visible to the naked eye and lasted for approximately 2 s.P@1exhib-ited selective phosphorescence enhancement response towards Pb^(2+),with a detection limit of 2.52μmol·L^(-1).Themain detection mechanism is the Pb—O coordination-induced phosphorescence enhancement in the system.Inter-estingly,P@1also functioned as a dual-channel probe for the rapid detection of Fe^(3+)ions through fluorescencequenching with a detection limit of 0.038μmol·L^(-1).The recognition mechanism may be attributed to the competi-tive energy absorption betweenP@1and Fe^(3+)ions.CCDC:2388502,1.
文摘The leaching of sulfuric acid converted product of scheelite in NH_(3)·H_(2)O−NH_(4)HCO_(3)solution was systemically studied to improve sulfuric acid conversion−ammonium salts leaching technology route for ammonium paratungstate production.The results showed that the WO_(3)leaching efficiency was about 99%under optimal conditions of 350 r/min,liquid-to-solid ratio of 3 mL/g,1 mol/L NH_(4)HCO_(3),4 mol/L NH_(3)·H_(2)O,25℃,and 15 min.During the leaching,CaSO_(4)almost had no change and was still in a banding or rod-like shape in short leaching time,while conglobate CaCO_(3)was gradually formed on the CaSO_(4)surface.A secondary reaction might occur between CaSO_(4)and WO_(4)^(2−),which could be restrained by a certain amount of CO_(3)^(2−)in the solution.There was no CaCO_(3)phase determined by XRD in leaching residue of converted product for scheelite concentrate under optimal conditions,which was different from that for synthetic scheelite.The leaching process could be explained by neutralization reaction of H_(2)WO_(4)and solid transformation of CaSO_(4)in NH_(3)·H_(2)O−NH_(4)HCO_(3)solution.
基金support from the National Key Scientific and Technological Infrastructure project “Earth System Science Numerical Simulator Facility” (Earth Lab)sponsored by the National Natural Science Foundation of China (Grant Nos. 42175132, 92044303, and 42205119)+2 种基金the National Key R&D Program (Grant Nos. 2020YFA0607802 and 2022YFC3703003)the CAS Information Technology Program (Grant No. CAS-WX2021SF-0107-02)the fellowship of China Postdoctoral Science Foundation (Grant No. 2022M723093)
文摘Scientific knowledge on the chemical compositions of fine particulate matter(PM_(2.5)) is essential for properly assessing its health and climate effects,and for decisionmakers to develop efficient mitigation strategies.A high-resolution PM_(2.5) chemical composition dataset(CAQRA-aerosol)is developed in this study,which provides hourly maps of organic carbon,black carbon,ammonium,nitrate,and sulfate in China from 2013 to 2020 with a horizontal resolution of 15 km.This paper describes the method,access,and validation results of this dataset.It shows that CAQRA-aerosol has good consistency with observations and achieves higher or comparable accuracy with previous PM_(2.5) composition datasets.Based on CAQRA-aerosol,spatiotemporal changes of different PM_(2.5) compositions were investigated from a national viewpoint,which emphasizes different changes of nitrate from other compositions.The estimated annual rate of population-weighted concentrations of nitrate is 0.23μg m^(−3)yr^(−1) from 2015 to 2020,compared with−0.19 to−1.1μg m^(−3)yr^(−1) for other compositions.The whole dataset is freely available from the China Air Pollution Data Center(https://doi.org/10.12423/capdb_PKU.2023.DA).
基金supported by the National Natural Science Foundation of China(Grant Nos.42372312,and 42172299)the Pyramid Talent Training Project of Beijing University of Civil Engineering and Architecture(Grant No.JDYC20220807).
文摘The progressive failure characteristics of geomaterial are a remarkable and challenging topic in geotechnical engineering.To study the effect of salt content and temperature on the progressive failure characteristics of frozen sodium sulfate saline sandy soil,a series of uniaxial compression tests were performed by integrating digital image correlation(DIC)technology into the testing apparatus.The evolution law of the uniaxial compression strength(UCS),the failure strain,and the formation of the shear band of the frozen sodium sulfate saline sandy soil were analyzed.The test results show that within the scope of this study,with the increase of salt content,both the UCS and the shear band angle initially decrease with increasing salt content before showing an increase.In contrast,the failure strain and the width of the shear band exhibit an initial increase followed by a decrease in the samples.In addition,to investigate the brittle failure characteristics of frozen sodium sulfate saline sandy soil,two classic brittleness evaluation methods were employed to quantitatively assess the brittleness level for the soil samples.The findings suggest that the failure characteristics under all test conditions in this study belong to the transition stage between brittle and ductile,indicating that frozen sodium sulfate saline sandy soil exhibits certain brittle behavior under uniaxial compression conditions,and the brittleness index basically decreases and then increases with the rise in salt content.
