Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant...Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant sodium alkyl glucosyl hydroxypropyl sulfonate(APGSHS) and zwitterionic surfactant octadecyl betaine(BS-18) is proposed. The performance of APGSHS/BS-18 mixed surfactant system was evaluated in terms of interfacial tension, emulsification capability, emulsion size and distribution, wettability alteration, temperature-resistance and salt-resistance. The emulsification speed was used to evaluate the emulsification ability of surfactant systems, and the results show that mixed surfactant systems can completely emulsify the crude oil into emulsions droplets even under low energy conditions. Meanwhile,the system exhibits good temperature and salt resistance. Finally, the best oil recovery of 25.45% is achieved for low permeability core by the mixed surfactant system with a total concentration of 0.3 wt%while the molar ratio of APGSHS:BS-18 is 4:6. The current study indicates that the anionic/zwitterionic mixed surfactant system can improve the oil flooding efficiency and is potential candidate for application in low permeability reservoirs.展开更多
Copper ions(Cu^(2+))are usually added to activate the sulfidized surface of zinc oxide minerals to enhance xanthate attachment using sulfidization xanthate flotation technology.The adsorption of Cu^(2+)and xanthate on...Copper ions(Cu^(2+))are usually added to activate the sulfidized surface of zinc oxide minerals to enhance xanthate attachment using sulfidization xanthate flotation technology.The adsorption of Cu^(2+)and xanthate on the sulfidized surface was investigated in various systems,and its effect on the surface hydrophobicity and flotation performance was revealed by multiple analytical methods and experiments.X-ray photoelectron spectroscopy(XPS)and time-of-flight secondary ion mass spectrometry(To F-SIMS)characterization demonstrated that the adsorption of Cu^(2+)on sulfidized smithsonite surfaces increased the active Cu—S content,regardless of treatment in any activation system.The sulfidized surface pretreated with NH_(4)^(+)-Cu^(2+)created favorable conditions for the adsorption of more Cu^(2+),significantly enhancing the smithsonite reactivity.Zeta potential determination,ultraviolet(UV)-visible spectroscopy,Fourier transform-infrared(FT-IR)measurements,and contact angle detection showed that xanthate was chemically adsorbed on the sulfidized surface,and its adsorption capacity in various systems was illustrated from qualitative and quantitative aspects.In comparison to the Na2S–Cu^(2+)and Cu^(2+)–Na2S–Cu^(2+)systems,xanthate exhibited a higher adsorption capacity on sulfidized smithsonite surfaces in NH_(4)^(+)-Cu^(2+)–Na2S–Cu^(2+)system.Hence,activation with Cu^(2+)–NH4+synergistic species prior to sulfidization significantly enhanced the mineral surface hydrophobicity,thereby increasing its flotation recovery.展开更多
Drug combination based on synergistic effect is commonly used in clinical practice,especially in the application of traditional medicine.Exploring the combination mechanism could help to better utilize this synergisti...Drug combination based on synergistic effect is commonly used in clinical practice,especially in the application of traditional medicine.Exploring the combination mechanism could help to better utilize this synergistic advantage.However,current research focuses more on the efficacy enhancing of drugs,while ignoring the toxicity reducing effects.Here,we established two drug synergy patterns based on the different situations of drugs and targets,in order to better illuminate the synergistic mechanism of drugs.展开更多
Korean spruce （Picea koraiensis Sieb. E1 Zucc.） is one of the main afforestation species in northern China. Seedling quality is a critical factor at planting time. To test whether the synergistic growth enhancement ...Korean spruce （Picea koraiensis Sieb. E1 Zucc.） is one of the main afforestation species in northern China. Seedling quality is a critical factor at planting time. To test whether the synergistic growth enhancement of Scotch pine （P. sylvestris var. mongolica） seedlings brought by the plant beneficial fungus Trichoderma virens （J.H. Mill., Giddens and A.A. Foster） Arx and ectomycorrhizal fungus （Suillus luteus （L.） Roussel.） can also benefit Korean spruce seed- lings, we examined the effects of S. luteus and T. virens on the growth of P. koraiensis seedlings and drought resistance of P. sylvestris var. mongolica in peat soils. The two fungi were added to sterilized peat soil in pots, and the plants were grown for 4 months. Seedling growth and physiological variables, including mycorrhizal colonization rate of roots, biomass, and chlorophyll content, were examined. The colonization rate of the mycorrhizal fungus on P. koraiensis exceeded 65 %, and the synergism between S. luteus and T. virens enhanced most of the variables for P. koraiensis seedlings after inoculation with S. luteus then 30 days later with T. virens as in our published results for seedlings of P. sylvestris var. mongolica. When seedlings of P. sylvestris var. mongolica were inoculated with this sequence, they became more drought tolerant. T. virens also induced S. luteus to produce -l,3-glucanase and chitinase. This inocu- lation sequence at planting can thus improve the quality of P. sylvestris var. mongolica and P. koraiensis seedlings and substantiates our previous results.展开更多
A novel nanofluid of modified carbon black(MCB)nanoparticles was initially developed for enhanced oil recovery(EOR)in low permeability reservoirs.The MCB nanoparticles were obtained via a three-step reaction involving...A novel nanofluid of modified carbon black(MCB)nanoparticles was initially developed for enhanced oil recovery(EOR)in low permeability reservoirs.The MCB nanoparticles were obtained via a three-step reaction involving modification by oxidation,acyl chlorination,and activated grafting.MCB nano-particles were spherically dispersed,with an average size of 72.3 nm.Compared with carbon black(CB)nanoparticles,dispersed MCB nanoparticles can effectively reduce the oil-water interfacial tension(IFT)to 10^(-2)mN/m and change the surface wettability of sand particles.Based on the results of core flooding experiments,the MCB nanoparticles exhibited a better EOR capacity than surfactants and CB nano-particles,and the final oil recovery was significantly increased by 27.27%.The core scanning test showed that the MCB nanoparticles could plug high permeability channels by adsorbing onto the surfaces of sand particles and forming larger aggregates that bridge across pores or throats,resulting in a higher swept volume.The synergistic effects of improved swept volume and oil displacement efficiency were the EOR mechanisms of the MCB nanoparticles.The studies indicate that these MCB nanoparticles have excellent potential for EOR in low permeability reservoirs.展开更多
Arm symmetrical PbS dendrite （ASD-PbS） nanostructures can be prepared on a large scale by a solvothermal process. The ASD-PbSs exhibit a three-dimensional symmetrical structure, and each dendrite grows multiple bran...Arm symmetrical PbS dendrite （ASD-PbS） nanostructures can be prepared on a large scale by a solvothermal process. The ASD-PbSs exhibit a three-dimensional symmetrical structure, and each dendrite grows multiple branches on the main trunk. Such unique ASD-PbSs can be combined with polyvinylidene fluoride （PVDF） to prepare a composite material with enhanced dielectric and microwave-absorption properties. A detailed investigation of the dependence of the dielectric properties on the frequency and temperature shows that the ASD-PbS/PVDF composite has an ultrahigh dielectric constant and a low percolation threshold. The dielectric permittivity is as high as 1,548 when the concentration of the ASD-PbS filler reaches 13.79 vol.% at 102 Hz, which is 150 times larger than that of pure PVDF, while the composite is as flexible as pure PVDF. Furthermore, the maximum reflection loss can reach -36.69 dB at 16.16 GHz with a filler content of only 2 wt.%, which indicates excellent microwave absorption. The loss mechanism is also elucidated. The present work demonstrates that the addition of metal sulfide microcrystals to polymer matrix composites provides a useful method for improving the dielectric and microwave-absorption properties.展开更多
Localized surface plasmon resonance(LSPR)of nanostructures and the interfacial charge transfer(CT)of semiconductor materials play essential roles in the study of optical and photoelectronic properties.In this paper,a ...Localized surface plasmon resonance(LSPR)of nanostructures and the interfacial charge transfer(CT)of semiconductor materials play essential roles in the study of optical and photoelectronic properties.In this paper,a composite substrate of Ag2S quantum dots(QDs)coated plasmonic Au bowtie nanoantenna(BNA)arrays with a metalinsulator-metal(MIM)configuration was built to study the synergistic effect of LSPR and interfacial CT using surface-enhanced Raman scattering(SERS)in the near-infrared(NIR)region.The Au BNA array structure with a large enhancement of the localized electric field(E-field)strongly enhanced the Raman signal of adsorbed p-aminothiophenol(PATP)probe molecules.Meanwhile,the broad enhanced spectral region was achieved owing to the coupling of LSPR The as-prepared Au BNA array structure facilitated enhancements of the excitation as well as the emission of Raman signal simultaneously,which was established by finite-difference time-domain simulation.Moreover,Ag2S semiconductor QDs were introduced into the BNA/PATP system to further enhance Raman signals,which benefited from the interfacial CT resonance in the BNA/Ag2S-QDs/PATP system.As a result,the Raman signals of PATP in the BNA/Ag2S-QDs/PATP system were strongly enhanced under 785 nm laser excitation due to the synergistic effect of E-field enhancement and interfacial CT.Furthermore,the SERS polarization dependence effeas of the BNA/Ag2S-QDs/PATP system were also investigated.The SERS spectra indicated that the polarization dependence of the substrate increased with decreasing polarization angles(θpola)of excitation from p-polarized(θpola=90°)excitation to s-polarized(θpola=0°)excitation.This study provides a strategy using the synergistic effect of interfacial CT and E-field enhancement for SERS applications and provides a guidance for the development of SERS study on semiconductor QD-based plasmonic substrates,and can be farther extended to other material-nanostructure systems for various optoelectronic and sensing applications.展开更多
Sorption of carbon tetrachloride （CT） by zero-valent iron （ZVI） is the rate-limiting step in the degradation of CT, so the sorption capacity of ZVl is of great importance. This experiment was aimed at enhancing th...Sorption of carbon tetrachloride （CT） by zero-valent iron （ZVI） is the rate-limiting step in the degradation of CT, so the sorption capacity of ZVl is of great importance. This experiment was aimed at enhancing the sorption of CT by ZVI and the degradation rate of CT by modification of surfactants. This study showed that ZVI modified by cationic surfactants has favorable synergistic effect on the degradation of CT. The CT degradation rate of ZVI modified by cetyl pyridinium bromide （CPB） was higher than that of the unmodified ZVI by 130%, and the CT degradation rate of ZVI modified by cetyl trimethyl ammonium bromide （CTAB） was higher than that of the unmodified ZVI by 81%. This study also showed that the best degradation effect is obtained at the near critical micelle concentrations （CMC） and that high loaded cationic surfactant does not have good synergistic effect on the degradation due to its hydrophilicity and the block in surface reduction sites. Furthermore degradation of CT by ZVI modified by nonionic surfactant has not positive effect on the degradation as the ionic surfactant and the ZVI modified by anionic surfactant has hardly any obvious effects on the degradation.展开更多
基金financially supported by National Natural Science Foundation of China(No.22302229)Beijing Municipal Excellent Talent Training Funds Youth Advanced Individual Project(No.2018000020124G163)。
文摘Emulsification is one of the important mechanisms of surfactant flooding. To improve oil recovery for low permeability reservoirs, a highly efficient emulsification oil flooding system consisting of anionic surfactant sodium alkyl glucosyl hydroxypropyl sulfonate(APGSHS) and zwitterionic surfactant octadecyl betaine(BS-18) is proposed. The performance of APGSHS/BS-18 mixed surfactant system was evaluated in terms of interfacial tension, emulsification capability, emulsion size and distribution, wettability alteration, temperature-resistance and salt-resistance. The emulsification speed was used to evaluate the emulsification ability of surfactant systems, and the results show that mixed surfactant systems can completely emulsify the crude oil into emulsions droplets even under low energy conditions. Meanwhile,the system exhibits good temperature and salt resistance. Finally, the best oil recovery of 25.45% is achieved for low permeability core by the mixed surfactant system with a total concentration of 0.3 wt%while the molar ratio of APGSHS:BS-18 is 4:6. The current study indicates that the anionic/zwitterionic mixed surfactant system can improve the oil flooding efficiency and is potential candidate for application in low permeability reservoirs.
基金supported by National Natural Science Foundation of China(No.52264026)Yunnan Fundamental Research Projects(Nos.202301AW070018,and 202101BE070001-009)。
文摘Copper ions(Cu^(2+))are usually added to activate the sulfidized surface of zinc oxide minerals to enhance xanthate attachment using sulfidization xanthate flotation technology.The adsorption of Cu^(2+)and xanthate on the sulfidized surface was investigated in various systems,and its effect on the surface hydrophobicity and flotation performance was revealed by multiple analytical methods and experiments.X-ray photoelectron spectroscopy(XPS)and time-of-flight secondary ion mass spectrometry(To F-SIMS)characterization demonstrated that the adsorption of Cu^(2+)on sulfidized smithsonite surfaces increased the active Cu—S content,regardless of treatment in any activation system.The sulfidized surface pretreated with NH_(4)^(+)-Cu^(2+)created favorable conditions for the adsorption of more Cu^(2+),significantly enhancing the smithsonite reactivity.Zeta potential determination,ultraviolet(UV)-visible spectroscopy,Fourier transform-infrared(FT-IR)measurements,and contact angle detection showed that xanthate was chemically adsorbed on the sulfidized surface,and its adsorption capacity in various systems was illustrated from qualitative and quantitative aspects.In comparison to the Na2S–Cu^(2+)and Cu^(2+)–Na2S–Cu^(2+)systems,xanthate exhibited a higher adsorption capacity on sulfidized smithsonite surfaces in NH_(4)^(+)-Cu^(2+)–Na2S–Cu^(2+)system.Hence,activation with Cu^(2+)–NH4+synergistic species prior to sulfidization significantly enhanced the mineral surface hydrophobicity,thereby increasing its flotation recovery.
基金This work was supported by the National Natural Science Foundation of China(No.82003982,82274313,82204746).
文摘Drug combination based on synergistic effect is commonly used in clinical practice,especially in the application of traditional medicine.Exploring the combination mechanism could help to better utilize this synergistic advantage.However,current research focuses more on the efficacy enhancing of drugs,while ignoring the toxicity reducing effects.Here,we established two drug synergy patterns based on the different situations of drugs and targets,in order to better illuminate the synergistic mechanism of drugs.
基金the National Natural Science Foundation of China (31170597, 31200484)the National Fiveyear Science and Technology Research Project (2012BAD19B0801)+1 种基金the Fundamental Research Funds for the Central Universities (2572014AA30)the National Forestry Bureau ‘‘948’’ Project (2009-4-39) for financial support
文摘Korean spruce （Picea koraiensis Sieb. E1 Zucc.） is one of the main afforestation species in northern China. Seedling quality is a critical factor at planting time. To test whether the synergistic growth enhancement of Scotch pine （P. sylvestris var. mongolica） seedlings brought by the plant beneficial fungus Trichoderma virens （J.H. Mill., Giddens and A.A. Foster） Arx and ectomycorrhizal fungus （Suillus luteus （L.） Roussel.） can also benefit Korean spruce seed- lings, we examined the effects of S. luteus and T. virens on the growth of P. koraiensis seedlings and drought resistance of P. sylvestris var. mongolica in peat soils. The two fungi were added to sterilized peat soil in pots, and the plants were grown for 4 months. Seedling growth and physiological variables, including mycorrhizal colonization rate of roots, biomass, and chlorophyll content, were examined. The colonization rate of the mycorrhizal fungus on P. koraiensis exceeded 65 %, and the synergism between S. luteus and T. virens enhanced most of the variables for P. koraiensis seedlings after inoculation with S. luteus then 30 days later with T. virens as in our published results for seedlings of P. sylvestris var. mongolica. When seedlings of P. sylvestris var. mongolica were inoculated with this sequence, they became more drought tolerant. T. virens also induced S. luteus to produce -l,3-glucanase and chitinase. This inocu- lation sequence at planting can thus improve the quality of P. sylvestris var. mongolica and P. koraiensis seedlings and substantiates our previous results.
基金supported by the National Key R&D Program of China(2018YFA0702400)National Natural Science Foundation of China(5207040347).
文摘A novel nanofluid of modified carbon black(MCB)nanoparticles was initially developed for enhanced oil recovery(EOR)in low permeability reservoirs.The MCB nanoparticles were obtained via a three-step reaction involving modification by oxidation,acyl chlorination,and activated grafting.MCB nano-particles were spherically dispersed,with an average size of 72.3 nm.Compared with carbon black(CB)nanoparticles,dispersed MCB nanoparticles can effectively reduce the oil-water interfacial tension(IFT)to 10^(-2)mN/m and change the surface wettability of sand particles.Based on the results of core flooding experiments,the MCB nanoparticles exhibited a better EOR capacity than surfactants and CB nano-particles,and the final oil recovery was significantly increased by 27.27%.The core scanning test showed that the MCB nanoparticles could plug high permeability channels by adsorbing onto the surfaces of sand particles and forming larger aggregates that bridge across pores or throats,resulting in a higher swept volume.The synergistic effects of improved swept volume and oil displacement efficiency were the EOR mechanisms of the MCB nanoparticles.The studies indicate that these MCB nanoparticles have excellent potential for EOR in low permeability reservoirs.
基金Acknowledgements This project was supported by the National Natural Science Foundation of China （Nos. 51472012, 51672013, 21521001, and 21431006）, and the Fundamental Research Funds for the Central Universities.
文摘Arm symmetrical PbS dendrite （ASD-PbS） nanostructures can be prepared on a large scale by a solvothermal process. The ASD-PbSs exhibit a three-dimensional symmetrical structure, and each dendrite grows multiple branches on the main trunk. Such unique ASD-PbSs can be combined with polyvinylidene fluoride （PVDF） to prepare a composite material with enhanced dielectric and microwave-absorption properties. A detailed investigation of the dependence of the dielectric properties on the frequency and temperature shows that the ASD-PbS/PVDF composite has an ultrahigh dielectric constant and a low percolation threshold. The dielectric permittivity is as high as 1,548 when the concentration of the ASD-PbS filler reaches 13.79 vol.% at 102 Hz, which is 150 times larger than that of pure PVDF, while the composite is as flexible as pure PVDF. Furthermore, the maximum reflection loss can reach -36.69 dB at 16.16 GHz with a filler content of only 2 wt.%, which indicates excellent microwave absorption. The loss mechanism is also elucidated. The present work demonstrates that the addition of metal sulfide microcrystals to polymer matrix composites provides a useful method for improving the dielectric and microwave-absorption properties.
基金Chinese Academy of Sciences(QYZDB-SSWSYS038)National Natural Science Foundation of China(11674178,11774340,91750205,61705227)+1 种基金K.C.Wong Education Foundation(GJTD-2018-08)Jilin Provincial Science&Technology Development Project(20180414019GH)。
文摘Localized surface plasmon resonance(LSPR)of nanostructures and the interfacial charge transfer(CT)of semiconductor materials play essential roles in the study of optical and photoelectronic properties.In this paper,a composite substrate of Ag2S quantum dots(QDs)coated plasmonic Au bowtie nanoantenna(BNA)arrays with a metalinsulator-metal(MIM)configuration was built to study the synergistic effect of LSPR and interfacial CT using surface-enhanced Raman scattering(SERS)in the near-infrared(NIR)region.The Au BNA array structure with a large enhancement of the localized electric field(E-field)strongly enhanced the Raman signal of adsorbed p-aminothiophenol(PATP)probe molecules.Meanwhile,the broad enhanced spectral region was achieved owing to the coupling of LSPR The as-prepared Au BNA array structure facilitated enhancements of the excitation as well as the emission of Raman signal simultaneously,which was established by finite-difference time-domain simulation.Moreover,Ag2S semiconductor QDs were introduced into the BNA/PATP system to further enhance Raman signals,which benefited from the interfacial CT resonance in the BNA/Ag2S-QDs/PATP system.As a result,the Raman signals of PATP in the BNA/Ag2S-QDs/PATP system were strongly enhanced under 785 nm laser excitation due to the synergistic effect of E-field enhancement and interfacial CT.Furthermore,the SERS polarization dependence effeas of the BNA/Ag2S-QDs/PATP system were also investigated.The SERS spectra indicated that the polarization dependence of the substrate increased with decreasing polarization angles(θpola)of excitation from p-polarized(θpola=90°)excitation to s-polarized(θpola=0°)excitation.This study provides a strategy using the synergistic effect of interfacial CT and E-field enhancement for SERS applications and provides a guidance for the development of SERS study on semiconductor QD-based plasmonic substrates,and can be farther extended to other material-nanostructure systems for various optoelectronic and sensing applications.
基金Project (No. 20030352) supported the Science and TechnologyProgram of Zhejiang Province, China
文摘Sorption of carbon tetrachloride （CT） by zero-valent iron （ZVI） is the rate-limiting step in the degradation of CT, so the sorption capacity of ZVl is of great importance. This experiment was aimed at enhancing the sorption of CT by ZVI and the degradation rate of CT by modification of surfactants. This study showed that ZVI modified by cationic surfactants has favorable synergistic effect on the degradation of CT. The CT degradation rate of ZVI modified by cetyl pyridinium bromide （CPB） was higher than that of the unmodified ZVI by 130%, and the CT degradation rate of ZVI modified by cetyl trimethyl ammonium bromide （CTAB） was higher than that of the unmodified ZVI by 81%. This study also showed that the best degradation effect is obtained at the near critical micelle concentrations （CMC） and that high loaded cationic surfactant does not have good synergistic effect on the degradation due to its hydrophilicity and the block in surface reduction sites. Furthermore degradation of CT by ZVI modified by nonionic surfactant has not positive effect on the degradation as the ionic surfactant and the ZVI modified by anionic surfactant has hardly any obvious effects on the degradation.
