Some processes of sulfating roasting and water leaching of crude Mianning RE concentrate ore, of fine Mianning RE concentrate ore, of Baotou RE concentrate ore and of their mixture were investigated.The result shows t...Some processes of sulfating roasting and water leaching of crude Mianning RE concentrate ore, of fine Mianning RE concentrate ore, of Baotou RE concentrate ore and of their mixture were investigated.The result shows that the mixture of Mianning and Baotou RE concentrate ore has the optimum leaching rate and rate of recovery when the mixture ratio is 1:4.The recovery rate of the mixture is higher by 14.76% than that of crude Mianning RE concentrate ore, by 5.0 % than that of Mianning fine RE concentrate ore and by 2.4 % than that of Baotou RE concentrate ore.展开更多
We present a comprehensive description and benchmark evaluation of the global–regional chemical transport model called the Emission and Atmospheric Processes Integrated and Coupled Community(EPICC)model.The framework...We present a comprehensive description and benchmark evaluation of the global–regional chemical transport model called the Emission and Atmospheric Processes Integrated and Coupled Community(EPICC)model.The framework incorporates(1)grid configuration,(2)transport dynamics,(3)chemical mechanisms,(4)aerosol processes,(5)wet/dry deposition parameterizations,and(6)heterogeneous chemistry treatments associated with sulfate,nitrous acid(HONO)chemistry,and aerosol/cloud–photolysis interactions(APIs/CPIs).Openly shared with the atmospheric research community,the model facilitates integration of advanced physicochemical schemes to enhance simulation accuracy.Globally,the model demonstrates realistic representations of ozone(O_(3))and aerosol optical depth.The EPICC model generally demonstrates robust performance in simulating regional concentrations of O_(3) and PM_(2.5)(and its components)in China.It successfully captures vertical profiles of both global and regional O_(3).Notably,the model mitigates frequently reported sulfate underestimations in highly industrialized regions of China.The model accurately captures two regional severe pollution episodes observed in eastern China(January/June 2021).Sensitivity experiments highlight the critical roles of heterogeneous chemical mechanisms associated with sulfate,HONO chemistry,APIs,and CPIs in capturing PM_(2.5) and O_(3) concentrations in China.Improved sulfate mechanisms result in an increase of approximately 32.4%(2.8μg m^(−3))in simulated winter sulfate concentrations when observations exceed 10μg m^(−3).Enhanced HONO elevates winter O_(3) and PM_(2.5) by≤20 and≤10μg m^(−3),respectively.Overall,CPIs dominate over APIs in improving O_(3) and PM_(2.5) simulations across China.Locally,APIs mitigate PM_(2.5) and O_(3) discrepancies in the Sichuan Basin.Seasonal cloud–chemistry coupling explains the weaker impact of PM_(2.5) in summer.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
In strong aggressive areas,Indonesian standards specify a maximum penetration of 30 mm.Concrete utilizes sulfate-resistant Portland Pozzolan Cement(PPC)for a target strength of 30 MPa,with and without silica fume and ...In strong aggressive areas,Indonesian standards specify a maximum penetration of 30 mm.Concrete utilizes sulfate-resistant Portland Pozzolan Cement(PPC)for a target strength of 30 MPa,with and without silica fume and plastic fiber(SR-SFF-sea and SR-N-SFF).Some samples of SR-N-SFF are immersed in the sea(SR-N-SFF-sea),while others are protected(SR-N-SFF-protected).Additionally,concrete using non-sulfate-resistant cement(NSR-sea)with a strength of 20.75 MPa was also evaluated.All samples were subjected to penetration depth testing according to the DIN EN 12390-8 standard,demonstrating that they met the penetration requirements for intense aggression.The study employed cylindrical samples measuring 15 cm in diameter and 30 cm in height to assess compressive strength and natural penetration fromthe split tensile test.Samples were placed into the sea at the fishing boat dock in Lampung,Indonesia,at 9 days of age following 7 days of immersion curing.The results indicated that sulfate-resistant Portland Composite Cement(PCC)is unsuitable for protected areas,as its strength is inferior to that of concrete submerged in seawater.Concrete featuring sulfate-resistant PCC,silica fume,and plastic fiber(SR-SFF-sea)exhibited lower strength compared to SR-N-SFF-protected samples.Conversely,SR-N-SFF-sea achieved the highest strength of 46 MPa at 56 days,with a notable increase in strength occurring from 21 to 56 days,while no increase in penetration depth was observed during this period.The standard penetration depth of SR-N-SFF-sea is 17.8mm,which can serve as a guideline for creating durable concrete in marine environments.展开更多
OBJECTIVE:To explore whether Gegen Qinlian decoction(葛根芩连汤,GQD)targets ferroptosis pathway to ameliorate experimental colitis in mice.METHODS:A mice model of dextran sulfate sodium(DSS)induced colitis was establi...OBJECTIVE:To explore whether Gegen Qinlian decoction(葛根芩连汤,GQD)targets ferroptosis pathway to ameliorate experimental colitis in mice.METHODS:A mice model of dextran sulfate sodium(DSS)induced colitis was established and therapeutic effects of GQD were determined by detecting body weight,disease activity index(DAI),colon length and histopathological changes.Then,the expression levels of inflammatory cytokines were detected by enzyme-linked immunosorbent assay,the expression levels of tight junction proteins were detected by immunohistochemistry and the expression levels of ferroptosis-associated proteins were detected by western blotting.RESULTS:GQD treatment attenuated weight loss and DAI score,increased colon length,ameliorated intestinal histopathological damage,inhibited colonic inflammatory cytokine release and enhanced epithelial barrier function in mice with ulcerative colitis(UC).Furthermore,GQD administration obviously improved the expression of ferroptosis-associated proteins(solute carrier family 7 member 11 and acyl-Co A synthetase long chain family member 4).CONCLUSION:GQD could exert a therapeutic effect on colitis by alleviating colon damage and promoting intestinal mucosal barrier repair in DSS-induced colitis mice through the inhibition of ferroptosis,which may provide an effective natural therapy for the treatment of UC.展开更多
This study developed a novel heterogeneous Vis-Photo+Fenton-like system by integrating visible-light-responsive Co_(3)O_(4)/TiO_(2) photocatalysis with peroxymonosulfate(PMS)activation for efficient atrazine(ATZ)degra...This study developed a novel heterogeneous Vis-Photo+Fenton-like system by integrating visible-light-responsive Co_(3)O_(4)/TiO_(2) photocatalysis with peroxymonosulfate(PMS)activation for efficient atrazine(ATZ)degradation.The synergistic process achieved complete ATZ removal within 60 min under near-neutral pH(6.9),outperform-ing individual Fenton-like(39%)and photocatalytic(24%)processes.Key factors influencing the degradation efficiency included light sources(UV>visible),pH(optimal at 6.9),catalyst dosage(0.01 g Co_(3)O_(4)/TiO_(2)),and PMS:ATZ molar ratio(1:2).The system exhibited a synergistic coefficient of 5.03(degradation)and 1.97(miner-alization),attributed to enhanced radical generation and accelerated Co^(3+)/Co^(2+)redox cycling through photoin-duced electron transfer.Intermediate analysis revealed dealkylation,dechlorination,and oxidation pathways,with reduced toxicity of by-products(e.g.,CEAT,CIAT)confirmed by ecotoxicity assessments.The mineralization efficiency(Vis-Photo+Fenton-like)reached 83.1%,significantly higher than that of standalone processes(Fenton-like:43.2%;photocatalysis:30.5%).The catalyst demonstrated excellent stability(nearly 90%recov-ery,<1μg/L Co leaching)and practical applicability.This study provides an efficient,sludge-free,and solar-compatible strategy for eliminating persistent herbicides in water treatment.展开更多
Thermochemical sulfate reduction(TSR)is an important organic-inorganic reaction that occurs within sedimentary basins and alters the original chemical compositions and isotopic structures of hydrocarbons in natural ga...Thermochemical sulfate reduction(TSR)is an important organic-inorganic reaction that occurs within sedimentary basins and alters the original chemical compositions and isotopic structures of hydrocarbons in natural gases.We used the GC-Py-GC-IRMS method to study TSR and obtained a novel finding related to intramolecular carbon isotope fractionation in natural propane.The results show that theΔC-T(δ^(13)C_(central)-13 C_(terminal))andδ^(13)C_(central)values significantly increased to 44.7‰and 11.9‰,respectively,with increasing TSR alteration.In contrast,the 13 C_(terminal)values of propane remained largely unaltered by the TSR reaction.This difference in position-specific isotope fractionation can be attributed to the central carbon’s reactivity being higher than that of terminal carbon during TSR.In sum,the results indicate that theδ^(13)C_(terminal)values of propane can serve as robust indicators for source rock identification of natural gas altered by post-generation reactions such as TSR and anaerobic microbial oxidation.展开更多
Respiratory inflammatory diseases disrupt bone metabolism and cause pathological bone loss.The lung-bone axis is established in chronic diseases like asthma and cystic fibrosis but is less studied in acute lung injury...Respiratory inflammatory diseases disrupt bone metabolism and cause pathological bone loss.The lung-bone axis is established in chronic diseases like asthma and cystic fibrosis but is less studied in acute lung injury(ALI),recently implicated in COVID-19-induced bone loss.This study examined the effects of LPS-induced ALI on bone phenotype and explored the role of 2-N,6-O sulfated chitosan(26SCS)in mitigating pneumonia-induced bone loss via inflammatory response modulation.Our findings show that 26SCS effectively reaches bone tissue after oral administration.It promotes macrophage polarization to the M2 phenotype,alleviating immune cascade reactions and inhibiting osteoclast-mediated bone resorption.Increased M2 macrophages support type H vessel formation,enhancing inflammatory bone vascularization.These effects foster a favorable osteogenic microenvironment and mitigate ALI-induced bone loss.While dexamethasone is effective in reducing inflammation,it can aggravate ALI-induced bone loss.Our research offers a therapeutic strategy targeting the lung-bone axis for inflammation-induced bone loss.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
The Ordovician Majiagou Formation(O1m)in the Ordos Basin is a crucial exploration field for natural gas,and exploration of the Ordovician middle assemblage(O_(1)m_(5)^(5-7))has recently yielded great breakthrough.The ...The Ordovician Majiagou Formation(O1m)in the Ordos Basin is a crucial exploration field for natural gas,and exploration of the Ordovician middle assemblage(O_(1)m_(5)^(5-7))has recently yielded great breakthrough.The Daniudi gas field provides a good case study to determine the gas source for the strata.The O_(1)m_(5)^(5-7)gas displays C1/C1-5 ratios of 0.932-0.985 and CO_(2)contents of 1.56%-11.75%,and the detectable H2S content ranges from 0.0002%to 1.8617%.Theδ^(13)C1,δ^(13)C2,δ^(13)CCO_(2),andδD_(1)values are−39.7‰to−35.6‰,−30.4‰to−23.7‰,−12.4‰to−4.6‰,and−204‰to−185‰,respectively.Identification of the gas origin and source indicates that the gaseous alkanes are commonly coal-derived gas.The gas was generated from the coal measures in the Taiyuan Formation(C_(3t))and subsequently migrated.A small amount of oil-associated gas,mainly from O1m carbonate source rocks,has been incorporated into the gas reservoir.The natural gas has experienced insignificant alteration by thermochemical sulfate reduction,and the relatively high levels of CO_(2)are probably associated with corrosion alteration of carbonate reservoirs by injected fluid during acid fracturing.展开更多
High-sulfur iron concentrates emit SO_(2)into the flue gas during pellet induration.To investigate the effect of the SO_(2)cycle on pellet quality in the grate-kiln process,sulfur balance analysis,thermodynamic calcul...High-sulfur iron concentrates emit SO_(2)into the flue gas during pellet induration.To investigate the effect of the SO_(2)cycle on pellet quality in the grate-kiln process,sulfur balance analysis,thermodynamic calculations,and pellet production experiments under simulated flue gas circulation conditions were conducted.The results indicated that SO_(2)circulation inhibited desulfurization and deteriorated pellet strength.SO_(2)absorption increased the pellet sulfur content to 0.70 wt.%during the downdraft drying phase,and the absorption could be aggravated by the moisture.The desulfurization rate of the preheating process was also decreased to 16.67%,resulting from the refractory sulfate generation.Sulfur content of the roasted pellets dropped to 0.13 wt.%because of the aluminosilicate generation.The finished pellet sulfur content further decreased to 0.08 wt.%due to the fresh air during the cooling process.Eventually,optimization measures were proposed when high-sulfur iron concentrates were used for oxidized pellet preparation.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
Sulfamethoxazole(SMZ)is a prevalent and recalcitrant micropollutant in water,posing a significant threat to both aquatic organisms and human health.Therefore,investigating the removal of SMZ is of critical importance....Sulfamethoxazole(SMZ)is a prevalent and recalcitrant micropollutant in water,posing a significant threat to both aquatic organisms and human health.Therefore,investigating the removal of SMZ is of critical importance.In order to investigate the effect of rare earth metal doping on the performance of activated persulfate oxidative degradation of SMZ,BiFeO_(3)with different Ce doping amounts was successfully prepared by a hydrothermal method.Then,it was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),scanning transmission electro n microscopy(STEM)and Brunauer-Emmett-Teller(BET)method.The performance of porous Ce/BiFeO_(3)in the catalytic activation of persulfate(PMS)for the degradation of SMZ in water was investigated using SMZ solution as a simulated wastewater.The impact of Ce doping rate,catalyst dosage,temperature variations,common anions,natural organic matter,and PMS concentration on SMZ removal was systematically evaluated.The characterization results show that the octahedral rhombic structure of Ce can be observed on the surface of this doped catalyst,and Ce doping does not change the crystalline shape of Ce/BiFeO_(3).The specific surface area of the doped catalyst increases,accompanied by an enlargement of pore size,thereby enhancing the catalyst's adsorption capacity and resistance to contamination by SMZ.Under the optimal conditions of 25℃,SMZ concentration of 20 mg/L,0.8 g/L PMS and 0.3 g/L 0.05Ce/BiFeO_(3)catalyst,the removal rate of SMZ reaches approximately 95%within35 min of reaction time.Even after five cycles of reuse,the degradation rate of SMZ remains above 88%,demonstrating the catalyst's good stability and reusability.Bursting experiments show that SO_(4)^(·-),·OH,1O_(2)and O_(2)^(·-)are involved in the catalytic degradation process,with 1O_(2)playing a dominant role.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
Sulfate attack-induced expansion of cement-treated aggregates in seasonally frozen regions is a well-known issue which causes continuous expansion in railway subgrades,and particularly in high-speed railways.According...Sulfate attack-induced expansion of cement-treated aggregates in seasonally frozen regions is a well-known issue which causes continuous expansion in railway subgrades,and particularly in high-speed railways.Accordingly,we investigated the influence of material proportions,the number of freeze-thaw(FT)cycles,and temperature gradients on the expansion mechanism of sulfate attack on cement-treated aggregates subjected to FT cycles.The conditions,laws,and dominant factors causing the expansion of aggregates were analyzed through swelling tests.The results indicate that under FT cycles,3%content cement-treated graded macadam only experiences slight deformation.The maximum strain of graded macadam attacked by 1%sodium sulfate content in each FT cycle is significantly larger than that of 3%content cement-treated graded macadam attacked by 1%sodium sulfate content.Using scanning electron microscopy,needle-like crystals were observed during sulfate attack of cement-treated graded macadam.Through quantitative analysis,we determined the recoverable and unrecoverable deformations of graded macadam under FT cycles.For graded macadam under sulfate attack,the expansion is mainly induced by periodic frost heave and salt expansion,as well as salt migration.For cement-treated graded macadam under sulfate attack,the expansion is mainly induced by chemical attack and salt migration.This study can serve as a reference for future research on the mechanics of sulfate attack on cement-treated aggregates that experience FT cycles,and provide theoretical support for methods that remediate the expansion induced by sulfate attack.展开更多
To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requir...To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requires immediate investigation.In view of this phenomenon,the durability of unit lining concrete is predicted by analyzing three key indicators:carbonation depth,relative dynamic elastic modulus,and residual quality.This prediction is achieved by integrating the Entropy Weight Method,Grey theory life prediction model and BP artificial neural networks using data from tests and predictions of these indicators.Then,the Entropy Weight-Grey theory-BP Network Model is compared with other methods to analyze the predicted life.Finally,verify the sci-entificity of this model,and the optimum silica fume content of unit concrete lining is verified.The results showed,1)The addition of silica fume will accelerate the carbonization of unit concrete lining,and slow down the freeze-thaw cycle and sulfate erosion.2)The utilization of artificial neural networks is essential for enhancing the realism of the data,as it emphasizes the significance of silica fume content.3)Silica fume content of 10%results in the longest life and is the most suitable for lining construction.4)A comparison between single-factor and multi-factor predictions indicates that the multi-factor approach yields a longer maximum life.This improvement can be attributed to the inclusion of additional factors,such as freeze-thaw cycles and carbonation,which enhance the predicted life when employing these methods.In conclusion,the Entropy Weight-Grey Theory-BP Network life prediction Model is well-suited for tunnel lining in the alpine sulfate area of northwest China.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
Pu-erh tea has been shown to reduce gut inflammation in dextran sulfate sodium(DSS)-induced mice.Also,we found abnormal liver cholesterol metabolism in DSS-induced mice.However,it's not clear how Pu-erh tea improv...Pu-erh tea has been shown to reduce gut inflammation in dextran sulfate sodium(DSS)-induced mice.Also,we found abnormal liver cholesterol metabolism in DSS-induced mice.However,it's not clear how Pu-erh tea improves DSS-induced impaired liver cholesterol metabolism.Here,we established the DSS-induced model and clarified that DSS exacerbated gut inflammation accompanied by disorders of liver cholesterol metabolism.Pu-erh tea reshaped gut microbes,limited gut oxidative stress and inflammation(nicotinamide adenine dinucleotide phosphate oxidase 2/reactive oxygen species/myeloid differentiation primary response protein 88/nuclear factor kappa-B,24.97%-52.89%),reduced gut bile acid reabsorption(up-regulation of farnesoid X receptor(FXR)/fibroblast growth factor 15,24.53%-55.91%),and promoted liver bile acid synthesis(up-regulation of peroxisome proliferator-activated receptor-α/cholesterol 7-alpha hydroxylase,34.65%-79.14%),thereby partly restoring liver cholesterol metabolism(regulated FXR/small heterodimer partner/sterol-regulatory element binding proteins,53.19%-95.40%).Altered bile acid metabolic profiles(increased chenodeoxycholic acid,ursodeoxycholic acid,lithocholic acid,etc.)may also improve liver cholesterol metabolism by altering gut and liver inflammation.Thus,gut microbial reshaping and altered bile acid metabolism may be key targets of Pu-erh tea for improving DSS-induced liver cholesterol metabolism disorders via the gut-gut microbe-bile acid-liver axis.展开更多
The paper presents experimental investigation results of crack pattern change in cement pastes caused by external sulfate attack(ESA).To visualize the formation and development of cracks in cement pastes under ESA,an ...The paper presents experimental investigation results of crack pattern change in cement pastes caused by external sulfate attack(ESA).To visualize the formation and development of cracks in cement pastes under ESA,an X-ray computed tomography(X-ray CT)was used,i e,the tomography system of Zeiss Xradia 510 versa.The results indicate that X-CT can monitor the development process and distribution characteristics of the internal cracks of cement pastes under ESA with attack time.In addition,the C3A content in the cement significantly affects the damage mode of cement paste specimens during sulfate erosion.The damage of ordinary Portland cement(OPC)pastes subjected to sulfate attack with high C3A content are severe,while the damage of sulfate resistant Portland cement(SRPC)pastes is much smaller than that of OPC pastes.Furthermore,a quadratic function describes the correlation between the crack volume fraction and development depth for two cement pastes immermed in sulfate solution.展开更多
文摘Some processes of sulfating roasting and water leaching of crude Mianning RE concentrate ore, of fine Mianning RE concentrate ore, of Baotou RE concentrate ore and of their mixture were investigated.The result shows that the mixture of Mianning and Baotou RE concentrate ore has the optimum leaching rate and rate of recovery when the mixture ratio is 1:4.The recovery rate of the mixture is higher by 14.76% than that of crude Mianning RE concentrate ore, by 5.0 % than that of Mianning fine RE concentrate ore and by 2.4 % than that of Baotou RE concentrate ore.
基金National Key Scientific and Technological Infrastructure project “Earth System Science Numerical Simulator Facility” (EarthLab)supported by the National Natural Science Foundation of China (Grant No. 92044302)the National Key Research Development Program of China (Grant No. 2022YFC3700703)
文摘We present a comprehensive description and benchmark evaluation of the global–regional chemical transport model called the Emission and Atmospheric Processes Integrated and Coupled Community(EPICC)model.The framework incorporates(1)grid configuration,(2)transport dynamics,(3)chemical mechanisms,(4)aerosol processes,(5)wet/dry deposition parameterizations,and(6)heterogeneous chemistry treatments associated with sulfate,nitrous acid(HONO)chemistry,and aerosol/cloud–photolysis interactions(APIs/CPIs).Openly shared with the atmospheric research community,the model facilitates integration of advanced physicochemical schemes to enhance simulation accuracy.Globally,the model demonstrates realistic representations of ozone(O_(3))and aerosol optical depth.The EPICC model generally demonstrates robust performance in simulating regional concentrations of O_(3) and PM_(2.5)(and its components)in China.It successfully captures vertical profiles of both global and regional O_(3).Notably,the model mitigates frequently reported sulfate underestimations in highly industrialized regions of China.The model accurately captures two regional severe pollution episodes observed in eastern China(January/June 2021).Sensitivity experiments highlight the critical roles of heterogeneous chemical mechanisms associated with sulfate,HONO chemistry,APIs,and CPIs in capturing PM_(2.5) and O_(3) concentrations in China.Improved sulfate mechanisms result in an increase of approximately 32.4%(2.8μg m^(−3))in simulated winter sulfate concentrations when observations exceed 10μg m^(−3).Enhanced HONO elevates winter O_(3) and PM_(2.5) by≤20 and≤10μg m^(−3),respectively.Overall,CPIs dominate over APIs in improving O_(3) and PM_(2.5) simulations across China.Locally,APIs mitigate PM_(2.5) and O_(3) discrepancies in the Sichuan Basin.Seasonal cloud–chemistry coupling explains the weaker impact of PM_(2.5) in summer.
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.
文摘In strong aggressive areas,Indonesian standards specify a maximum penetration of 30 mm.Concrete utilizes sulfate-resistant Portland Pozzolan Cement(PPC)for a target strength of 30 MPa,with and without silica fume and plastic fiber(SR-SFF-sea and SR-N-SFF).Some samples of SR-N-SFF are immersed in the sea(SR-N-SFF-sea),while others are protected(SR-N-SFF-protected).Additionally,concrete using non-sulfate-resistant cement(NSR-sea)with a strength of 20.75 MPa was also evaluated.All samples were subjected to penetration depth testing according to the DIN EN 12390-8 standard,demonstrating that they met the penetration requirements for intense aggression.The study employed cylindrical samples measuring 15 cm in diameter and 30 cm in height to assess compressive strength and natural penetration fromthe split tensile test.Samples were placed into the sea at the fishing boat dock in Lampung,Indonesia,at 9 days of age following 7 days of immersion curing.The results indicated that sulfate-resistant Portland Composite Cement(PCC)is unsuitable for protected areas,as its strength is inferior to that of concrete submerged in seawater.Concrete featuring sulfate-resistant PCC,silica fume,and plastic fiber(SR-SFF-sea)exhibited lower strength compared to SR-N-SFF-protected samples.Conversely,SR-N-SFF-sea achieved the highest strength of 46 MPa at 56 days,with a notable increase in strength occurring from 21 to 56 days,while no increase in penetration depth was observed during this period.The standard penetration depth of SR-N-SFF-sea is 17.8mm,which can serve as a guideline for creating durable concrete in marine environments.
基金National Natural Science Foundation Project:Study on the Mechanism of Gegen Qinlian Decoction in Reshaping Macrophage Polarization via Nicotinamide Adenine Dinucleotide Phosphate Oxidase 2-Mediated Neutrophil Extracellular Traps Formation for the Treatment of Ulcerative Colitis with Dampness-Heat Syndrome(No.82505455)。
文摘OBJECTIVE:To explore whether Gegen Qinlian decoction(葛根芩连汤,GQD)targets ferroptosis pathway to ameliorate experimental colitis in mice.METHODS:A mice model of dextran sulfate sodium(DSS)induced colitis was established and therapeutic effects of GQD were determined by detecting body weight,disease activity index(DAI),colon length and histopathological changes.Then,the expression levels of inflammatory cytokines were detected by enzyme-linked immunosorbent assay,the expression levels of tight junction proteins were detected by immunohistochemistry and the expression levels of ferroptosis-associated proteins were detected by western blotting.RESULTS:GQD treatment attenuated weight loss and DAI score,increased colon length,ameliorated intestinal histopathological damage,inhibited colonic inflammatory cytokine release and enhanced epithelial barrier function in mice with ulcerative colitis(UC).Furthermore,GQD administration obviously improved the expression of ferroptosis-associated proteins(solute carrier family 7 member 11 and acyl-Co A synthetase long chain family member 4).CONCLUSION:GQD could exert a therapeutic effect on colitis by alleviating colon damage and promoting intestinal mucosal barrier repair in DSS-induced colitis mice through the inhibition of ferroptosis,which may provide an effective natural therapy for the treatment of UC.
基金supported by the Financial Supports of the National Natural Science Foundation of China(Nos.51508056,52370030 and 42007352)the Chongqing Postgraduate Joint Training Base Project(No.JDLHPYJD2022005)the special fund of Henan Key Labora-tory of Water Pollution Control and Rehabilitation Technology(No.CJSZ2024001).
文摘This study developed a novel heterogeneous Vis-Photo+Fenton-like system by integrating visible-light-responsive Co_(3)O_(4)/TiO_(2) photocatalysis with peroxymonosulfate(PMS)activation for efficient atrazine(ATZ)degradation.The synergistic process achieved complete ATZ removal within 60 min under near-neutral pH(6.9),outperform-ing individual Fenton-like(39%)and photocatalytic(24%)processes.Key factors influencing the degradation efficiency included light sources(UV>visible),pH(optimal at 6.9),catalyst dosage(0.01 g Co_(3)O_(4)/TiO_(2)),and PMS:ATZ molar ratio(1:2).The system exhibited a synergistic coefficient of 5.03(degradation)and 1.97(miner-alization),attributed to enhanced radical generation and accelerated Co^(3+)/Co^(2+)redox cycling through photoin-duced electron transfer.Intermediate analysis revealed dealkylation,dechlorination,and oxidation pathways,with reduced toxicity of by-products(e.g.,CEAT,CIAT)confirmed by ecotoxicity assessments.The mineralization efficiency(Vis-Photo+Fenton-like)reached 83.1%,significantly higher than that of standalone processes(Fenton-like:43.2%;photocatalysis:30.5%).The catalyst demonstrated excellent stability(nearly 90%recov-ery,<1μg/L Co leaching)and practical applicability.This study provides an efficient,sludge-free,and solar-compatible strategy for eliminating persistent herbicides in water treatment.
基金supported by the Helium Enrichment and Detection in Natural Gas Reservoirs Related to Oil and Gas Fields project(Grant No.2025ZD1010500)the Deep Earth Probe and Mineral Resources Exploration―National Science and Technology Major Project.-。
文摘Thermochemical sulfate reduction(TSR)is an important organic-inorganic reaction that occurs within sedimentary basins and alters the original chemical compositions and isotopic structures of hydrocarbons in natural gases.We used the GC-Py-GC-IRMS method to study TSR and obtained a novel finding related to intramolecular carbon isotope fractionation in natural propane.The results show that theΔC-T(δ^(13)C_(central)-13 C_(terminal))andδ^(13)C_(central)values significantly increased to 44.7‰and 11.9‰,respectively,with increasing TSR alteration.In contrast,the 13 C_(terminal)values of propane remained largely unaltered by the TSR reaction.This difference in position-specific isotope fractionation can be attributed to the central carbon’s reactivity being higher than that of terminal carbon during TSR.In sum,the results indicate that theδ^(13)C_(terminal)values of propane can serve as robust indicators for source rock identification of natural gas altered by post-generation reactions such as TSR and anaerobic microbial oxidation.
基金supported by the Key Program of the National Natural Science Foundation of China(32230059)the Basic Science Center Program(T2288102)+3 种基金the Foundation of Frontiers Sciesnce Center for Materiobiology and Dynamic Chemistry(JKVD1211002)the National Natural Science Foundation of China(32401128)the Postdoctoral Fellowship Program of CPSF(GZC20230793)Shanghai Post-doctoral Excellence Program(2023251)。
文摘Respiratory inflammatory diseases disrupt bone metabolism and cause pathological bone loss.The lung-bone axis is established in chronic diseases like asthma and cystic fibrosis but is less studied in acute lung injury(ALI),recently implicated in COVID-19-induced bone loss.This study examined the effects of LPS-induced ALI on bone phenotype and explored the role of 2-N,6-O sulfated chitosan(26SCS)in mitigating pneumonia-induced bone loss via inflammatory response modulation.Our findings show that 26SCS effectively reaches bone tissue after oral administration.It promotes macrophage polarization to the M2 phenotype,alleviating immune cascade reactions and inhibiting osteoclast-mediated bone resorption.Increased M2 macrophages support type H vessel formation,enhancing inflammatory bone vascularization.These effects foster a favorable osteogenic microenvironment and mitigate ALI-induced bone loss.While dexamethasone is effective in reducing inflammation,it can aggravate ALI-induced bone loss.Our research offers a therapeutic strategy targeting the lung-bone axis for inflammation-induced bone loss.
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.
基金sponsored by National Natural Science Foundation of China(Grant Nos.U2244209,42172149,42488101,and 42141021).
文摘The Ordovician Majiagou Formation(O1m)in the Ordos Basin is a crucial exploration field for natural gas,and exploration of the Ordovician middle assemblage(O_(1)m_(5)^(5-7))has recently yielded great breakthrough.The Daniudi gas field provides a good case study to determine the gas source for the strata.The O_(1)m_(5)^(5-7)gas displays C1/C1-5 ratios of 0.932-0.985 and CO_(2)contents of 1.56%-11.75%,and the detectable H2S content ranges from 0.0002%to 1.8617%.Theδ^(13)C1,δ^(13)C2,δ^(13)CCO_(2),andδD_(1)values are−39.7‰to−35.6‰,−30.4‰to−23.7‰,−12.4‰to−4.6‰,and−204‰to−185‰,respectively.Identification of the gas origin and source indicates that the gaseous alkanes are commonly coal-derived gas.The gas was generated from the coal measures in the Taiyuan Formation(C_(3t))and subsequently migrated.A small amount of oil-associated gas,mainly from O1m carbonate source rocks,has been incorporated into the gas reservoir.The natural gas has experienced insignificant alteration by thermochemical sulfate reduction,and the relatively high levels of CO_(2)are probably associated with corrosion alteration of carbonate reservoirs by injected fluid during acid fracturing.
基金supported by the Science and Technology Innovation Program of Hunan Province(Nos.2023RC1025 and 2024RC3022)the Technology Special Program Project of China Minmetals Corporation(No.2021ZXA04)the Major Scientific Research Projects of Inner Mongolia Baotou Steel Union Co.,Ltd.(No.HKF202300356).
文摘High-sulfur iron concentrates emit SO_(2)into the flue gas during pellet induration.To investigate the effect of the SO_(2)cycle on pellet quality in the grate-kiln process,sulfur balance analysis,thermodynamic calculations,and pellet production experiments under simulated flue gas circulation conditions were conducted.The results indicated that SO_(2)circulation inhibited desulfurization and deteriorated pellet strength.SO_(2)absorption increased the pellet sulfur content to 0.70 wt.%during the downdraft drying phase,and the absorption could be aggravated by the moisture.The desulfurization rate of the preheating process was also decreased to 16.67%,resulting from the refractory sulfate generation.Sulfur content of the roasted pellets dropped to 0.13 wt.%because of the aluminosilicate generation.The finished pellet sulfur content further decreased to 0.08 wt.%due to the fresh air during the cooling process.Eventually,optimization measures were proposed when high-sulfur iron concentrates were used for oxidized pellet preparation.
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Project supported by the National Key Research and Development Program(2022YFC3204900)Jiangsu Province Construction System Technology Project(2023ZD108)。
文摘Sulfamethoxazole(SMZ)is a prevalent and recalcitrant micropollutant in water,posing a significant threat to both aquatic organisms and human health.Therefore,investigating the removal of SMZ is of critical importance.In order to investigate the effect of rare earth metal doping on the performance of activated persulfate oxidative degradation of SMZ,BiFeO_(3)with different Ce doping amounts was successfully prepared by a hydrothermal method.Then,it was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),scanning transmission electro n microscopy(STEM)and Brunauer-Emmett-Teller(BET)method.The performance of porous Ce/BiFeO_(3)in the catalytic activation of persulfate(PMS)for the degradation of SMZ in water was investigated using SMZ solution as a simulated wastewater.The impact of Ce doping rate,catalyst dosage,temperature variations,common anions,natural organic matter,and PMS concentration on SMZ removal was systematically evaluated.The characterization results show that the octahedral rhombic structure of Ce can be observed on the surface of this doped catalyst,and Ce doping does not change the crystalline shape of Ce/BiFeO_(3).The specific surface area of the doped catalyst increases,accompanied by an enlargement of pore size,thereby enhancing the catalyst's adsorption capacity and resistance to contamination by SMZ.Under the optimal conditions of 25℃,SMZ concentration of 20 mg/L,0.8 g/L PMS and 0.3 g/L 0.05Ce/BiFeO_(3)catalyst,the removal rate of SMZ reaches approximately 95%within35 min of reaction time.Even after five cycles of reuse,the degradation rate of SMZ remains above 88%,demonstrating the catalyst's good stability and reusability.Bursting experiments show that SO_(4)^(·-),·OH,1O_(2)and O_(2)^(·-)are involved in the catalytic degradation process,with 1O_(2)playing a dominant role.
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National Natural Science Foundation of China(Nos.42171130 and 42301158)Pilot Project of China’s Strength in Transportation for the Central Research Institute(No.QG2021-1-4-7)National Key Technology Research and Development Program of the Ministry of Science and Technology of China(No.2021YFB2601200).
文摘Sulfate attack-induced expansion of cement-treated aggregates in seasonally frozen regions is a well-known issue which causes continuous expansion in railway subgrades,and particularly in high-speed railways.Accordingly,we investigated the influence of material proportions,the number of freeze-thaw(FT)cycles,and temperature gradients on the expansion mechanism of sulfate attack on cement-treated aggregates subjected to FT cycles.The conditions,laws,and dominant factors causing the expansion of aggregates were analyzed through swelling tests.The results indicate that under FT cycles,3%content cement-treated graded macadam only experiences slight deformation.The maximum strain of graded macadam attacked by 1%sodium sulfate content in each FT cycle is significantly larger than that of 3%content cement-treated graded macadam attacked by 1%sodium sulfate content.Using scanning electron microscopy,needle-like crystals were observed during sulfate attack of cement-treated graded macadam.Through quantitative analysis,we determined the recoverable and unrecoverable deformations of graded macadam under FT cycles.For graded macadam under sulfate attack,the expansion is mainly induced by periodic frost heave and salt expansion,as well as salt migration.For cement-treated graded macadam under sulfate attack,the expansion is mainly induced by chemical attack and salt migration.This study can serve as a reference for future research on the mechanics of sulfate attack on cement-treated aggregates that experience FT cycles,and provide theoretical support for methods that remediate the expansion induced by sulfate attack.
基金funded by the Technology Funding Scheme of China Construction Second Engineering Bureau LTD(2020ZX150002)the National Natural Science Foundation Project of China(12262018).
文摘To address the challenges posed by tunnel construction in the alpine region,silica fume mixed concrete is commonly used as a construction material.The correlation between silica fume content and the lining life requires immediate investigation.In view of this phenomenon,the durability of unit lining concrete is predicted by analyzing three key indicators:carbonation depth,relative dynamic elastic modulus,and residual quality.This prediction is achieved by integrating the Entropy Weight Method,Grey theory life prediction model and BP artificial neural networks using data from tests and predictions of these indicators.Then,the Entropy Weight-Grey theory-BP Network Model is compared with other methods to analyze the predicted life.Finally,verify the sci-entificity of this model,and the optimum silica fume content of unit concrete lining is verified.The results showed,1)The addition of silica fume will accelerate the carbonization of unit concrete lining,and slow down the freeze-thaw cycle and sulfate erosion.2)The utilization of artificial neural networks is essential for enhancing the realism of the data,as it emphasizes the significance of silica fume content.3)Silica fume content of 10%results in the longest life and is the most suitable for lining construction.4)A comparison between single-factor and multi-factor predictions indicates that the multi-factor approach yields a longer maximum life.This improvement can be attributed to the inclusion of additional factors,such as freeze-thaw cycles and carbonation,which enhance the predicted life when employing these methods.In conclusion,the Entropy Weight-Grey Theory-BP Network life prediction Model is well-suited for tunnel lining in the alpine sulfate area of northwest China.
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.
基金supported by the National Natural Science Foundation of China funded project(32172627)Chongqing Modern Tea Technology System for Efficient Agriculture in Mountainous Areas 2022[8]the Germplasm Creation Research Program of Southwest University。
文摘Pu-erh tea has been shown to reduce gut inflammation in dextran sulfate sodium(DSS)-induced mice.Also,we found abnormal liver cholesterol metabolism in DSS-induced mice.However,it's not clear how Pu-erh tea improves DSS-induced impaired liver cholesterol metabolism.Here,we established the DSS-induced model and clarified that DSS exacerbated gut inflammation accompanied by disorders of liver cholesterol metabolism.Pu-erh tea reshaped gut microbes,limited gut oxidative stress and inflammation(nicotinamide adenine dinucleotide phosphate oxidase 2/reactive oxygen species/myeloid differentiation primary response protein 88/nuclear factor kappa-B,24.97%-52.89%),reduced gut bile acid reabsorption(up-regulation of farnesoid X receptor(FXR)/fibroblast growth factor 15,24.53%-55.91%),and promoted liver bile acid synthesis(up-regulation of peroxisome proliferator-activated receptor-α/cholesterol 7-alpha hydroxylase,34.65%-79.14%),thereby partly restoring liver cholesterol metabolism(regulated FXR/small heterodimer partner/sterol-regulatory element binding proteins,53.19%-95.40%).Altered bile acid metabolic profiles(increased chenodeoxycholic acid,ursodeoxycholic acid,lithocholic acid,etc.)may also improve liver cholesterol metabolism by altering gut and liver inflammation.Thus,gut microbial reshaping and altered bile acid metabolism may be key targets of Pu-erh tea for improving DSS-induced liver cholesterol metabolism disorders via the gut-gut microbe-bile acid-liver axis.
基金Funded by Chinese National Natural Science Foundation of China(No.U2006224)。
文摘The paper presents experimental investigation results of crack pattern change in cement pastes caused by external sulfate attack(ESA).To visualize the formation and development of cracks in cement pastes under ESA,an X-ray computed tomography(X-ray CT)was used,i e,the tomography system of Zeiss Xradia 510 versa.The results indicate that X-CT can monitor the development process and distribution characteristics of the internal cracks of cement pastes under ESA with attack time.In addition,the C3A content in the cement significantly affects the damage mode of cement paste specimens during sulfate erosion.The damage of ordinary Portland cement(OPC)pastes subjected to sulfate attack with high C3A content are severe,while the damage of sulfate resistant Portland cement(SRPC)pastes is much smaller than that of OPC pastes.Furthermore,a quadratic function describes the correlation between the crack volume fraction and development depth for two cement pastes immermed in sulfate solution.
