The effects of isothermal holding time on the semisolid microstructure of Mg-9Al-1Si(mass fraction,%)alloy were investigated.The research results indicate that the Mg-9Al-1Si alloy with non-dendritic microstructure ca...The effects of isothermal holding time on the semisolid microstructure of Mg-9Al-1Si(mass fraction,%)alloy were investigated.The research results indicate that the Mg-9Al-1Si alloy with non-dendritic microstructure can be produced by the semi-solid isothermal heat treatment.With holding time varying from 5 to 30 min,the volume fraction of liquid is gradually enlarged from 29.3%to 38.6%,the morphology ofα-Mg grains changes from initial dendritic shape to spherical types and their average sizes increases from 41.1 to 56.1μm.In addition,during the isothermal heat treatment,the eutectic Mg2Si phase changes from the initial Chinese script shape to granule and/or polygon shape in Mg-9Al-1Si alloy.The modification of Mg2Si phase is possibly attributed to a shift of the eutectic composition of the liquid in semi-solid slurries,towards lower silicon contents with increasing Al content due to a redistribution of Al during isothermal heat treatment.展开更多
In this study,ecofriendly and economic carboxy-terminated plant fibers(PFs)were used as adsorbents for the effective in-syringe solid phase extraction(IS-SPE)of fluoroquinolone(FQ)residues from water.Based on the ther...In this study,ecofriendly and economic carboxy-terminated plant fibers(PFs)were used as adsorbents for the effective in-syringe solid phase extraction(IS-SPE)of fluoroquinolone(FQ)residues from water.Based on the thermal esterification and etherification reaction of cellulose hydroxy with citric acid(CA)and sodium chloroacetate in aqueous solutions,carboxy groups grafted onto cotton,cattail,and corncob fibers were fabricated.Compared with carboxy-terminated corncob and cotton,CA-modified cattail with more carboxy groups showed excellent adsorption capacity for FQs.The modified cattail fibers were reproducible and reusable with relative standard deviations of 3.2%-4.2% within 10 cycles of adsorptiondesorption.A good extraction efficiency of 71.3%-80.9% was achieved after optimizing the extraction condition.Based on carboxylated cattail,IS-SPE coupled with ultra-performance liquid chromatography with a photodiode array detector was conducted to analyze FQs in environmental water samples.High sensitivity with limit of detections of 0.08-0.25 mg/L and good accuracy with recoveries of 83.8%-111.7% were obtained.Overall,the simple and environment-friendly modified waste PFs have potential applications in the effective extraction and detection of FQs in natural waters.展开更多
In this study,two novel spherical/hollow metal-organic frameworks were successfully synthesized,and further modified by a mild non-covalent modification strategy with dopamine and 1,4-benzenedithiol(BDT)as polymeric m...In this study,two novel spherical/hollow metal-organic frameworks were successfully synthesized,and further modified by a mild non-covalent modification strategy with dopamine and 1,4-benzenedithiol(BDT)as polymeric monomers to obtain pB DT@PDA-Ni-MOF and p BDT@PDA-Ni/Co-MOF,respectively.The results showed that the above MOFs possessed extremely fast adsorption rates and ideal adsorption capacities for sulfonamides(SAs)and the modified MOFs exhibited enhanced adsorption capacities for SAs owing to a large number of additional functional groups.Then,benefit of their regular morphology and size,a facile syringe-assisted dispersive solid phase extraction(S-DSPE)method was developed for efficient detection of SAs,which will provide a powerful tool for monitoring trace level of SAs in aqueous environment.展开更多
基金Project(HEUFT05038)supported by the Basic Research Foundation of Harbin Engineering University,ChinaProject(2009AA03Z423)supported by the National High-Tech Research and Development Program of China
文摘The effects of isothermal holding time on the semisolid microstructure of Mg-9Al-1Si(mass fraction,%)alloy were investigated.The research results indicate that the Mg-9Al-1Si alloy with non-dendritic microstructure can be produced by the semi-solid isothermal heat treatment.With holding time varying from 5 to 30 min,the volume fraction of liquid is gradually enlarged from 29.3%to 38.6%,the morphology ofα-Mg grains changes from initial dendritic shape to spherical types and their average sizes increases from 41.1 to 56.1μm.In addition,during the isothermal heat treatment,the eutectic Mg2Si phase changes from the initial Chinese script shape to granule and/or polygon shape in Mg-9Al-1Si alloy.The modification of Mg2Si phase is possibly attributed to a shift of the eutectic composition of the liquid in semi-solid slurries,towards lower silicon contents with increasing Al content due to a redistribution of Al during isothermal heat treatment.
基金supported by the National Natural Science Foundation of China(Grant Nos.:81703469 and 81973277)Open Fund of the State Key Laboratory of Quality Research in Chinese Medicine,University of Macao(Grant No.:SKL-QRCM(UM)-2020-2022,QRCM-OP21007)the World-Class Universities(Disciplines)and the Characteristic Development Guidance Funds for the Central Universities(Grant No.:PY3A012).
文摘In this study,ecofriendly and economic carboxy-terminated plant fibers(PFs)were used as adsorbents for the effective in-syringe solid phase extraction(IS-SPE)of fluoroquinolone(FQ)residues from water.Based on the thermal esterification and etherification reaction of cellulose hydroxy with citric acid(CA)and sodium chloroacetate in aqueous solutions,carboxy groups grafted onto cotton,cattail,and corncob fibers were fabricated.Compared with carboxy-terminated corncob and cotton,CA-modified cattail with more carboxy groups showed excellent adsorption capacity for FQs.The modified cattail fibers were reproducible and reusable with relative standard deviations of 3.2%-4.2% within 10 cycles of adsorptiondesorption.A good extraction efficiency of 71.3%-80.9% was achieved after optimizing the extraction condition.Based on carboxylated cattail,IS-SPE coupled with ultra-performance liquid chromatography with a photodiode array detector was conducted to analyze FQs in environmental water samples.High sensitivity with limit of detections of 0.08-0.25 mg/L and good accuracy with recoveries of 83.8%-111.7% were obtained.Overall,the simple and environment-friendly modified waste PFs have potential applications in the effective extraction and detection of FQs in natural waters.
基金supported by the National Key R&D Program of China(No.2019YFC1905501)the National Natural Science Foundation of China(Nos.22104145 and 22174129)+3 种基金Nature Science Foundation of Zhejiang Province(No.LZY21E030001)Natural Science Foundation of Gansu Province(No.21JR7RA078)Youth Collaborative Innovation Alliance Fund of LICP(No.HZJJ21–06)the“Light of West China”Program from Chinese Academy of Science。
文摘In this study,two novel spherical/hollow metal-organic frameworks were successfully synthesized,and further modified by a mild non-covalent modification strategy with dopamine and 1,4-benzenedithiol(BDT)as polymeric monomers to obtain pB DT@PDA-Ni-MOF and p BDT@PDA-Ni/Co-MOF,respectively.The results showed that the above MOFs possessed extremely fast adsorption rates and ideal adsorption capacities for sulfonamides(SAs)and the modified MOFs exhibited enhanced adsorption capacities for SAs owing to a large number of additional functional groups.Then,benefit of their regular morphology and size,a facile syringe-assisted dispersive solid phase extraction(S-DSPE)method was developed for efficient detection of SAs,which will provide a powerful tool for monitoring trace level of SAs in aqueous environment.
