In ultra-deep and large well sections,high collapse stresses and diminished annular return velocity present significant challenges to wellbore cleaning.With increasing depth,rising temperature and pressure constrain t...In ultra-deep and large well sections,high collapse stresses and diminished annular return velocity present significant challenges to wellbore cleaning.With increasing depth,rising temperature and pressure constrain the regulation of displacement and drilling fluid rheology,impairing the fluid’s capacity to transport cuttings effectively.A precise understanding of cuttings settlement behavior and terminal velocity is therefore essential for optimizing their removal.This study accounts for variations in wellbore temperature and pressure,incorporates non-spherical cuttings and wellbore diameter parameters,and develops accordingly a simplified model to predict terminal settlement velocity.Thecuttings carrying ratio is introduced as a metric for evaluatingwellbore cleanliness.Findings reveal that temperature and pressure fluctuations can alter terminal velocity by up to 3.4%.Cuttings shape plays a crucial role,with block-shaped cuttings requiring higher annular return velocity than flake-shaped ones at the same carrying ratio.As wellbore size increases,the minimum required carrying flow rate rises nonlinearly,though the rate of increase gradually declines.For a Φ444.5mmwellbore,a carrying ratio of at least 0.6 is recommended.Terminal velocity decreases with increasing consistency coefficient,particularly in high-viscosity regimes.The proposed carrying ratio offers a more accurate and practical assessment of wellbore cleanliness.展开更多
Imaging dynamics of membrane proteins of live cells in a wash-free and real-time manner has been a challenging task. Herein, we report unprecedented applications of malachite green(MG), an organic dye widely used in p...Imaging dynamics of membrane proteins of live cells in a wash-free and real-time manner has been a challenging task. Herein, we report unprecedented applications of malachite green(MG), an organic dye widely used in pigment industry, as a switchable fluorophore to monitor membrane enzymes or noncatalytic proteins in live cells. Conformationally flexible MG is non-fluorescent in aqueous solution, yet covalent binding with endogenous proteins of cells significantly enhances its fluorescence at 670 nm by restricting flexibility of dye. Integrating a phosphate-caged quinone methide precursor with MG yielded a covalent labeling fluorogenic probe, allowing real-time imaging of membrane alkaline phosphatase(ALP,a model catalytic protein) activity in live cells with over 100-fold enhancement of fluorescence intensity.Moreover, MG is also applicable to image non-catalytic protein by conjugation with protein-specific ligand. A fluorogenic probe consisted of c-RGDf K peptide and MG proved to be compatible with wash-free and real-time visualization of non-catalytic integrin α_(v)β_(3) in live cells with high contrast.展开更多
To improve the selective separation performance of silica nanofibers(SiO_(2)NFs)for cesium ions(Cs+)and overcome the defects of Prussian blue nanoparticles(PB NPs),PB/SiO_(2)-NH_(2)NFs were prepared to remove Cs^(+)fr...To improve the selective separation performance of silica nanofibers(SiO_(2)NFs)for cesium ions(Cs+)and overcome the defects of Prussian blue nanoparticles(PB NPs),PB/SiO_(2)-NH_(2)NFs were prepared to remove Cs^(+)from water.Among them,3-aminopropyltriethoxysilane(APTES)underwent an alkylation reaction with SiO_(2),resulting in the formation of a dense Si-O-Si network structure that decorated the surface of SiO_(2)NFs.Meanwhile,the amino functional groups in APTES combined with Fe3+and then reacted with Fe2+to form PB NPs,which anchored firmly on the aminoated SiO_(2)NFs surface.In our experiment,the maxi-mumadsorption capacity of PB/SiO_(2)-NH_(2)NFs was 111.38 mg/g,which was 31.5mg/g higher than that of SiO_(2)NFs.At the same time,after the fifth cycle,the removal rate of Cs^(+)by PB/SiO_(2)-NH_(2)NFs adsorbent was 75.36%±3.69%.In addition,the adsorption isotherms and adsorption kinetics of PB/SiO_(2)-NH_(2)NFs were combined with the Freundlich model and the quasi-two-stage fitting model,respectively.Further mechanism analysis showed that the bond between PB/SiO_(2)-NH_(2)NFs and Cs^(+)was mainly a synergistic action of ion exchange,electrostatic adsorption and membrane separation.展开更多
Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the pro...Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the problem of how to control graphene to form desired Gr/Cu composite is not well solved. This paper aims at exploring the best parameters for preparing graphene with different layers on Cu foil by chemical vapor deposition(CVD)method and studying the effects of different layers graphene on Gr/Cu composite’s electrical conductivity. Graphene grown on single-sided and double-sided copper was prepared for Gr/Cu and Gr/Cu/Gr composites. The resultant electrical conductivity of Gr/Cu composites increased with decreasing graphene layers and increasing graphene volume fraction. The Gr/Cu/Gr composite with monolayer graphene owns volume fraction of less than 0.002%,producing the best electrical conductivity up to59.8 ×10^(6)S/m,equivalent to 104.5% IACS and 105.3% pure Cu foil.展开更多
The dilemma for the synthesis of covalent organic frameworks(COFs)is crystallinity and stability.Herein,we present the synthesis of a single-crystalline amide-linked COF,and demonstrate its excellent chemical as well ...The dilemma for the synthesis of covalent organic frameworks(COFs)is crystallinity and stability.Herein,we present the synthesis of a single-crystalline amide-linked COF,and demonstrate its excellent chemical as well as thermal stabilities.This study will inspire the synthesis of a wide spectrum of highly crystalline and stable COFs,promote their structure-property investigations and boost their applications in selective gas adsorption,storage and separation.展开更多
Chiral covalent organic frameworks(COFs)have shown promising applications in asymmetric catalysis,enantiomer separation and chiral recognition due to their tunable structures and permanent porosity.Currently,synthesis...Chiral covalent organic frameworks(COFs)have shown promising applications in asymmetric catalysis,enantiomer separation and chiral recognition due to their tunable structures and permanent porosity.Currently,synthesis of chiral COFs mainly relies on direct-synthesis method which requires asymmetric monomers to polymerize and crystallize with symmetric monomers and post-synthesis method which has been greatly limited to having complete reactions with the micro-/meso-sized pores of COFs.Recently,the synthesis of two-dimensional COFs by covalent replacement of chiral competitor has been reported.Herein,we present the synthesis of three types of 3D COFs with tunable chirality using chiral amino acid derivative surfactant as inducer in water under ambient conditions.The hydrogen bonds and electrostatic interactions between amino acid derivative surfactant and monomers as well as their precursors facilitate the transfer of the chirality.展开更多
基金partly supported by the National Natural Science Foundation of China(52304045)the Open Fund(PLN2023-40)of the National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University)the Open Fund(2024-KFKT-08)of China National Petroleum Corporation Science and Technology Research Institute.
文摘In ultra-deep and large well sections,high collapse stresses and diminished annular return velocity present significant challenges to wellbore cleaning.With increasing depth,rising temperature and pressure constrain the regulation of displacement and drilling fluid rheology,impairing the fluid’s capacity to transport cuttings effectively.A precise understanding of cuttings settlement behavior and terminal velocity is therefore essential for optimizing their removal.This study accounts for variations in wellbore temperature and pressure,incorporates non-spherical cuttings and wellbore diameter parameters,and develops accordingly a simplified model to predict terminal settlement velocity.Thecuttings carrying ratio is introduced as a metric for evaluatingwellbore cleanliness.Findings reveal that temperature and pressure fluctuations can alter terminal velocity by up to 3.4%.Cuttings shape plays a crucial role,with block-shaped cuttings requiring higher annular return velocity than flake-shaped ones at the same carrying ratio.As wellbore size increases,the minimum required carrying flow rate rises nonlinearly,though the rate of increase gradually declines.For a Φ444.5mmwellbore,a carrying ratio of at least 0.6 is recommended.Terminal velocity decreases with increasing consistency coefficient,particularly in high-viscosity regimes.The proposed carrying ratio offers a more accurate and practical assessment of wellbore cleanliness.
基金financially supported by the National Natural Science Foundation of China (No. 22077031)the Research Program of State Key Laboratory of Bioreactor Engineeringthe Fundamental Research Funds for the Central Universities。
文摘Imaging dynamics of membrane proteins of live cells in a wash-free and real-time manner has been a challenging task. Herein, we report unprecedented applications of malachite green(MG), an organic dye widely used in pigment industry, as a switchable fluorophore to monitor membrane enzymes or noncatalytic proteins in live cells. Conformationally flexible MG is non-fluorescent in aqueous solution, yet covalent binding with endogenous proteins of cells significantly enhances its fluorescence at 670 nm by restricting flexibility of dye. Integrating a phosphate-caged quinone methide precursor with MG yielded a covalent labeling fluorogenic probe, allowing real-time imaging of membrane alkaline phosphatase(ALP,a model catalytic protein) activity in live cells with over 100-fold enhancement of fluorescence intensity.Moreover, MG is also applicable to image non-catalytic protein by conjugation with protein-specific ligand. A fluorogenic probe consisted of c-RGDf K peptide and MG proved to be compatible with wash-free and real-time visualization of non-catalytic integrin α_(v)β_(3) in live cells with high contrast.
基金supported by the College Students Extracur-ricular Innovation and Entrepreneurship Fund Project of Changzhou University(No.ZMF21020079)the Natural Sci-ence Fund for Colleges and Universities in Jiangsu Province(No.18KJB610001)+4 种基金the Natural Science Foundation of Jiangsu Province(No.BK20180964)the Science and Technology Project of Changzhou City(No.CJ20210119)the Natural Science Foun-dation of China(No.22075032)the National Key Research and Development Program(No.2021YFC3001104)the Natural Sci-ence Foundation of Xinjiang Uygur Autonomous Region(Nos.2020D01A49,2020D01B25 and 2020D01B26).
文摘To improve the selective separation performance of silica nanofibers(SiO_(2)NFs)for cesium ions(Cs+)and overcome the defects of Prussian blue nanoparticles(PB NPs),PB/SiO_(2)-NH_(2)NFs were prepared to remove Cs^(+)from water.Among them,3-aminopropyltriethoxysilane(APTES)underwent an alkylation reaction with SiO_(2),resulting in the formation of a dense Si-O-Si network structure that decorated the surface of SiO_(2)NFs.Meanwhile,the amino functional groups in APTES combined with Fe3+and then reacted with Fe2+to form PB NPs,which anchored firmly on the aminoated SiO_(2)NFs surface.In our experiment,the maxi-mumadsorption capacity of PB/SiO_(2)-NH_(2)NFs was 111.38 mg/g,which was 31.5mg/g higher than that of SiO_(2)NFs.At the same time,after the fifth cycle,the removal rate of Cs^(+)by PB/SiO_(2)-NH_(2)NFs adsorbent was 75.36%±3.69%.In addition,the adsorption isotherms and adsorption kinetics of PB/SiO_(2)-NH_(2)NFs were combined with the Freundlich model and the quasi-two-stage fitting model,respectively.Further mechanism analysis showed that the bond between PB/SiO_(2)-NH_(2)NFs and Cs^(+)was mainly a synergistic action of ion exchange,electrostatic adsorption and membrane separation.
基金supported substantially by the Southwest Jiaotong University for Material and Financial Support。
文摘Graphene(Gr)has unique properties including high electrical conductivity;Thus,graphene/copper(Gr/Cu)composites have attracted increasing attention to replace traditional Cu for electrical applications. However,the problem of how to control graphene to form desired Gr/Cu composite is not well solved. This paper aims at exploring the best parameters for preparing graphene with different layers on Cu foil by chemical vapor deposition(CVD)method and studying the effects of different layers graphene on Gr/Cu composite’s electrical conductivity. Graphene grown on single-sided and double-sided copper was prepared for Gr/Cu and Gr/Cu/Gr composites. The resultant electrical conductivity of Gr/Cu composites increased with decreasing graphene layers and increasing graphene volume fraction. The Gr/Cu/Gr composite with monolayer graphene owns volume fraction of less than 0.002%,producing the best electrical conductivity up to59.8 ×10^(6)S/m,equivalent to 104.5% IACS and 105.3% pure Cu foil.
基金We thank financial support from National Natural Science Foundation of China(52061135103 and 52173296)Structure characterizations were supported by Instrumental Analysis and Research Center of Sun Yat-sen University.
文摘The dilemma for the synthesis of covalent organic frameworks(COFs)is crystallinity and stability.Herein,we present the synthesis of a single-crystalline amide-linked COF,and demonstrate its excellent chemical as well as thermal stabilities.This study will inspire the synthesis of a wide spectrum of highly crystalline and stable COFs,promote their structure-property investigations and boost their applications in selective gas adsorption,storage and separation.
基金supported by the National Natural Science Foundation of China(52061135103,51873236,52203287)Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.23yxqntd002).
文摘Chiral covalent organic frameworks(COFs)have shown promising applications in asymmetric catalysis,enantiomer separation and chiral recognition due to their tunable structures and permanent porosity.Currently,synthesis of chiral COFs mainly relies on direct-synthesis method which requires asymmetric monomers to polymerize and crystallize with symmetric monomers and post-synthesis method which has been greatly limited to having complete reactions with the micro-/meso-sized pores of COFs.Recently,the synthesis of two-dimensional COFs by covalent replacement of chiral competitor has been reported.Herein,we present the synthesis of three types of 3D COFs with tunable chirality using chiral amino acid derivative surfactant as inducer in water under ambient conditions.The hydrogen bonds and electrostatic interactions between amino acid derivative surfactant and monomers as well as their precursors facilitate the transfer of the chirality.
