It is a well-known fact that sirolimus(SRL) undergoes degradation process via hydrolysis in aqueous media, leading to incorrect assessment of drug amount and thus release characteristics of formulations.The main objec...It is a well-known fact that sirolimus(SRL) undergoes degradation process via hydrolysis in aqueous media, leading to incorrect assessment of drug amount and thus release characteristics of formulations.The main objective of the present study was to evaluate the effect of nonionic surfactants in media on invitro release profiles for sirolimus eluting stents(SES) coated with biodegradable polymeric matrix.Phosphate buffer and acetate buffer incorporating nonionic surfactants with varying concentrations were examined for adequate solubility and stability(by RP-HPLC). Good sink condition was achieved in phosphate buffer(at pH 4.0) with 1.0% Tween 20, 1.0% Brij 35% and 0.5% Brij 58. Hydrodynamic size(by DLS) and the micelle-water partition coefficient(P) with standard free energy of solubilization(ΔGs°) of drug were evaluated to get some understanding about the solubilization phenomena. About 80% of drug release during the period of 48 h was achieved in optimized drug release media which was 1.0% Tween20 in phosphate buffer pH 4.0. The obtained accelerated SRL release profile in optimized medium correlated well with the real time in-vitro release in phosphate buffer(pH 7.4). Surface morphology changes(by SEM), changes in gravimetric weights and molecular weight change(by GPC) were examined before and after drug release to understand the drug release mechanism which explains that the polymer did not undergo degradation during the drug release.展开更多
The interfacial properties and rheological behavior of surfactant/polymer complex systems were measured to investigate the association behavior of the associating polymer.Compared with the pure surfactant solution,the...The interfacial properties and rheological behavior of surfactant/polymer complex systems were measured to investigate the association behavior of the associating polymer.Compared with the pure surfactant solution,there are two inflection points in the surface tension curve for the surfactant/polymer complex systems.The two inflection points are dependent on the surfactant type and polymer concentration.The effect of surfactant on the rheological behavior of polymer can be divided into two aspects.First,the addition of short-chain betaine surfactant is detrimental to the viscosity of polymer solution due to the electrostatic shielding effect.Second,long-chain betaine surfactant also reduces the viscosity of polymer solutions at low concentrations.However,when the concentration of the long-chain betaine surfactant is relatively high,the long-chain betaine surfactant could form worm-like micelles that promote the intermolecular association and thus increase the number of associating junctions,thereby resulting in the augmentation of viscosity.So it is necessary to apply the long-chain betaine surfactant to build the polymer/surfactant flooding system.The interaction model between surfactant and polymer is proposed,which is different from the traditional‘Three-Region Model’.展开更多
Nickel nanoparticles can work as catalyst for the aquathermolysis reactions between water and heavy oil.A homogeneous and stable suspension is needed to carry the nickel nanoparticles into deeper reservoirs.This study...Nickel nanoparticles can work as catalyst for the aquathermolysis reactions between water and heavy oil.A homogeneous and stable suspension is needed to carry the nickel nanoparticles into deeper reservoirs.This study conducts a detailed investigation on how to achieve stabilized nickel nanoparticle suspensions with the use of surfactant and polymer.To stabilize the nickel nanoparticle suspension,three surfactants including sodium dodecyl sulfate,cationic surfactant cetyltrimethylammonium bromide and polyoxyalkalene amine derivative(Hypermer) along with xanthan gum polymer were introduced into the nickel nanoparticle suspension.Static stability tests and zeta potential measurements were conducted to determine the polymer/surfactant recipes yielding the most stable nickel nanoparticle suspensions.Dynamic micromodel flow tests were also conducted on three suspensions to reveal how the nickel nanoparticles would travel and distribute in porous media.Test results showed that when the injection was initiated,most nickel nanoparticles were able to pass through the gaps between the sand grains and produced in the outlet of the micromodel;only a small number of the nickel nanoparticles were attached to the grain surface.A higher nickel concentration in the suspension may lead to agglomeration of nickel nanoparticles in porous media,while a lower concentration can mitigate this agglomeration.Moreover,clusters tended to form when the nickel nanoparticle suspension carried an electrical charge opposite to that of the porous media.Follow-up waterflood was initiated after the nanofluid injection.It was found that the waterflood could not flush away the nanoparticles that were remaining in the micromodel.展开更多
To understand the displacement characteristics and remaining oil displacement process by the surfactant/polymer(SP) flooding in cores with different pore structures, the effects of pore structure on the enhanced oil r...To understand the displacement characteristics and remaining oil displacement process by the surfactant/polymer(SP) flooding in cores with different pore structures, the effects of pore structure on the enhanced oil recovery of SP flooding was investigated at the pore, core and field scales through conducting experiments on natural core samples with three typical types of pore structures. First, the in-situ nuclear magnetic resonance core flooding test was carried out to capture the remaining oil variation features in the water flooding and SP flooding through these three types of cores. Subsequently, at the core scale, displacement characteristics and performances of water flooding and SP flooding in these three types of cores were evaluated based on the full-size core flooding tests. Finally, at the field scale, production characteristics of SP flooding in the bimodal sandstone reservoir and multimodal conglomerate reservoir were compared using the actual field production data. The results show: as the pore structure gets more and more complex, the water flooding performance gets poorer, but the incremental recovery factor by SP flooding gets higher;the SP flooding can enhance the producing degree of oil in 1-3 μm pores in the unimodal and bimodal core samples, while it produces largely oil in medium and large pores more than 3 μm in pore radius in the multimodal core sample. The core flooding test using full-size core sample demonstrates that the injection of SP solution can significantly raise up the displacement pressure of the multimodal core sample, and greatly enhance recovery factor by emulsifying the remaining oil and enlarging swept volume. Compared with the sandstone reservoir, the multimodal conglomerate reservoir is more prone to channeling. With proper profile control treatments to efficiently enlarge the microscopic and macroscopic swept volumes, SP flooding in the conglomerate reservoir can contribute to lower water cuts and longer effective durations.展开更多
Hollow calcium carbonate(CaCO3) microspheres with different morphologies were synthesized via the precipitation reaction of calcium chloride with sodium carbonate in the presence of different surfactant-polymer comple...Hollow calcium carbonate(CaCO3) microspheres with different morphologies were synthesized via the precipitation reaction of calcium chloride with sodium carbonate in the presence of different surfactant-polymer complexes.The selected anionic surfactants were sodium dodecyl sulfonate(SDS) and sodium dodecyl benzenesulfonate(SDBS),respectively.The selected water-soluble polymers were polyacrylic acid(PAA) and polyvinyl pyrrolidone(PVP).In this work,SDS-PVP "pearl-necklace model" micellar complex was formed via hydrophobic effectiveness between SDS and PVP and it served as the spherical template to generate spherical CaCO3 aggregates with hollow microspheres composed of about 500 nm irregular shaped particles.SDS-PAA complexes and SDBS-PAA complexes formed "core-shell model" aggregates with calcium ions serving as the medium to link the anionic surfactant and the polymer.SDS-PAA "core-shell model" aggregates would act as templates for hollow CaCO3 microspheres consisting of 30―50 nm irregular shaped crystallites.SDBS-PAA "core-shell model" aggregates served as the spherical aggregate templates to generate spherical CaCO3 aggregates consisted of many small spherical particles which had grown together.All the obtained CaCO3 hollow microspheres are calcite particles.This research may provide new insight into the control of morphologies of hollow CaCO3 microspheres in the presence of surfactantpolymer complexes.展开更多
Orthogonal-test-design method has been used to determine the optimal formula by phase behavior and interfacial tension studies, respectively. The effect of each component of two alkaline/surfactant/polymer flooding sy...Orthogonal-test-design method has been used to determine the optimal formula by phase behavior and interfacial tension studies, respectively. The effect of each component of two alkaline/surfactant/polymer flooding systems on interfacial tension is discussed, in which a low-price natural mixed carboxylate (SDC) is used as the major surfactant. The results indicate that the optimal composition is SDC (0.5%), alkaline NaHCO3/Na2CO3 with mass ratio of 1 (1.0%), and hydrolyzed polyacrylamide(0.1%). In the coreflood experiment, their oil recovery is increased by about 25.2% and 26.8% original oil in place, respectively.展开更多
By means of changing the detection angle, the molecular conformation of a new type of polymer surfactant, acrylamide-poly(oxyethykene alkyl ether)acrylate-anionic monomer random copolymer, was studied by x-ray photoel...By means of changing the detection angle, the molecular conformation of a new type of polymer surfactant, acrylamide-poly(oxyethykene alkyl ether)acrylate-anionic monomer random copolymer, was studied by x-ray photoelectron spectroscopy(XPS) in detail.展开更多
Based on deep analysis of ASP/oil emulsions flow behavior characteristic,a mathematical description of non-Newtonian emulsion was developed,and variation of rheological behaviors along the percolation flow direction w...Based on deep analysis of ASP/oil emulsions flow behavior characteristic,a mathematical description of non-Newtonian emulsion was developed,and variation of rheological behaviors along the percolation flow direction was given.The effects of emulsions rheological behavior on oil recovery were quantity researched by a 2-D positive rhythm profile geological model.The result shows that the high viscosity and reduction of water phase permeability by emulsification can improve low-middle layer flow rate and enhance sweep efficiency,and the enhancement degree is related with emulsification degree.The study result can be used as reference for scheme design and production performance forecast during ASP flooding.展开更多
A surfactant-assisted method for preparing colloidal spheres with narrow size distribution from a polydispersed azo polymer has been developed in this work. The colloidal spheres were formed through gradual hydrophobi...A surfactant-assisted method for preparing colloidal spheres with narrow size distribution from a polydispersed azo polymer has been developed in this work. The colloidal spheres were formed through gradual hydrophobic aggregation of the polymeric chains in THF-H2O dispersion media, which was induced by a steady increase in the water content. Results showed that the addition of a small amount of surfactant (SDBS) could significantly narrow the size distribution of the colloidal spheres. The size distribution of the colloidal spheres was determined by the concentrations of azo polymer and the amount of surfactant in the systems. When the concentrations of polymer and surfactant amount were in a proper range, colloidal spheres with narrow size distribution could be obtained. The colloidal spheres formed by this method could be elongated along the polarization direction of the laser beams upon Ar+ laser irradiation. The colloidal spheres are considered to be a new type of the colloid-based functional materials.展开更多
With tunable local electronic environment,high mass density of MN4sites,and ease of preparation,metal-organic conjugated coordinative polymer(CCP) with inherent electronic conductivity provides a promising alternative...With tunable local electronic environment,high mass density of MN4sites,and ease of preparation,metal-organic conjugated coordinative polymer(CCP) with inherent electronic conductivity provides a promising alternative to the well-known M-N-C electrocatalysts.Herein,the coordination reaction between Cu^(2+)and 1,2,4,5-tetraaminobenzene(TAB) was conducted on the surface of metallic Cu nanowires,forming a thin layer of CuN4-based CCP(Cu-TAB) on the Cu nanowire.More importantly,interfacial transfer of electrons from Cu core to the CuN4-based CCP nanoshell was observed within the resulting CuTAB@Cu,which was found to enrich the local electronic density of the CuN4sites.As such,the CuTAB@Cu demonstrates much improved affinity to the*COOH intermediate formed from the rate determining step;the energy barrier for C-C coupling,which is critical to convert CO_(2)into C2products,is also decreased.Accordingly,it delivers a current density of-9.1 mA cm^(-2)at a potential as high as 0.558 V(vs.RHE) in H-type cell and a Faraday efficiency of 46.4% for ethanol.This work emphasizes the profound role of interfacial interaction in tuning the local electronic structure and activating the CuN4-based CCPs for efficient electroreduction of CO_(2).展开更多
Taking the pilot test area of polymer enhanced foam flooding in Y oilfield as the prototype, a numerical core model was established, and the polymer enhanced foam formulation system was optimized by analyzing the resi...Taking the pilot test area of polymer enhanced foam flooding in Y oilfield as the prototype, a numerical core model was established, and the polymer enhanced foam formulation system was optimized by analyzing the resistance factor and the change rule of oil recovery of different formulation systems. Research shows that the higher the polymer concentration, the greater the resistance factor, and the more obvious the sealing effect formed in the formation. The concentration of surfactant has a greater impact on the resistance factor. With the increase of surfactant concentration, the resistance factor increases significantly, and the plugging effect of foam agent on core is significantly enhanced. With the increase of gas-liquid ratio, the resistance factor first increases and then decreases. When the gas-liquid ratio is 1:1, the resistance is the largest, and the foam agent has the strongest plugging effect on the core. The optimal formula system of polymer enhanced foam flooding in Y oilfield is: polymer concentration is 1200 mg/L, surfactant concentration is 0.25 wt%, gas-liquid ratio is 1:1.展开更多
A mixture of nine biphenyl nitrile compounds with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 min. The buffer system contained...A mixture of nine biphenyl nitrile compounds with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 min. The buffer system contained 100 mmol/L sodium dodecyl sulfate (SDS), 80 mmol/L sodium cholate (SC), 0.81% heptane, 7.5% n-butanol, 10% acetonitrile and 10 mmol/L borate. The addition of SC, organic modifiers, sample preparation and temperature all showed remarkable effect on the separation. Meanwhile, the MEEKC method was briefly compared with micellar electrokinetic chromatography (MEKC) method.展开更多
The objective of this research was to show a way to conduct rejuvenation of aged polymer modified asphalt binder(PMB) successfully.To fully evaluate and understand the rejuvenation of aged PMB,the Penetration grade te...The objective of this research was to show a way to conduct rejuvenation of aged polymer modified asphalt binder(PMB) successfully.To fully evaluate and understand the rejuvenation of aged PMB,the Penetration grade tests including penetration,soften point,ductility and elastic recovery and SuperpaveTM PG grade tests including DSR,BBR and DDT were conducted.The rejuvenation effect of aged PMB by utilizing a fluid recycling agent in common use for binder rejuvenation was evaluated.And then the compound rejuvenation effect of aged PMB by utilizing the recycling agent with a new modifying additive for binder modification was evaluated.The experimental results indicated that the recycling agent in common use currently does not apply to polymer modified asphalt binder rejuvenation.But the recycling agent together with the modifying additive can restore the characteristics of aged polymer modified binder very well.Therefore,compound rejuvenation of polymer modified asphalt binder is recommended.展开更多
Polyester polyether block copolymer(PPBC) was synthesized by ester-exchange and polycondensation reactions using dimethyl terephthalate(DMT),ethylene glycol(EG) and polyethylene glycol(PEG) as monomer.The effects of P...Polyester polyether block copolymer(PPBC) was synthesized by ester-exchange and polycondensation reactions using dimethyl terephthalate(DMT),ethylene glycol(EG) and polyethylene glycol(PEG) as monomer.The effects of PEG molecular weight,mol ratio of DMT to PEG(nDMT/nPEG),temperature and time of polycondensation reaction and vacuum degree in the reaction system on the surface tension and critical micelle concentration(CMC) of PPBC aqueous solution were studied.It was found that both the molecular weight and the concentration of PEG can affect PPBC's surface activity obviously,and the optimum synthesis condition of PPBC used as surfactant is as follows:PEG molecular weight is 1500,mol ratio of DMT to PEG is 3,temperature and time of polycondensation reaction is 260℃×1h,vacuum degree of condensation reaction is 0.03-0.05 MPa.It was proved by surface tension measurement of PPBC aqueous solution that the PPBC synthesized in this condition is a good surfactant with excellent surfactivity.展开更多
The interaction of poly(ethylene oxide)(PEO)with the ionic surfactants,sodium dodecylsulfate(SDS)and cetyltrimethylammonium chloride(CTAC)respectively,in aqueous solutions containing a certain concentration of NH_4Cl,...The interaction of poly(ethylene oxide)(PEO)with the ionic surfactants,sodium dodecylsulfate(SDS)and cetyltrimethylammonium chloride(CTAC)respectively,in aqueous solutions containing a certain concentration of NH_4Cl, is studied by the viscosity measurement.It has been found that the ion-dipole interaction between PEO and ionic surfactants is changed considerably by the organic salt.For anionic suffactant of SDS,the addition of NH_4Cl into solution strengthens the interaction between PEO and the headgrou...展开更多
Three A-shaped nitropyrimidine derivatives with benzyl or furfuryl as bridge havebeen synthesized. They possess shorter absorption wavelengths (λ<sub>cut-off</sub>)【400 nm) andhigher βμ values (around ...Three A-shaped nitropyrimidine derivatives with benzyl or furfuryl as bridge havebeen synthesized. They possess shorter absorption wavelengths (λ<sub>cut-off</sub>)【400 nm) andhigher βμ values (around 10<sup>-46</sup> esu). The second order nonlinear optical coefficient d<sub>33</sub> ofpoled BNPMOPMDA/PMMA doped film is 1.2-2.0×10<sup>-9</sup> esu obtained by in-situ SHGmeasurements. It can be expected that the chromophore-functionalized polymer containinghigher number density of synthesized chromophore as side chain will be the potential blue-light transparent frequency doubling materials.展开更多
Two coordination polymers, namely {[Mn(HL_1)(phen)]·4H_2O}_n(1) and [Co_2(HL_2)_2(H_2O)_2]_n(2) have been constructed hydrothermally using H_3L_1 and H_3L_2(H_3L_1 = 2-(5-carboxypyridin-2-yl)terephthalic acid, H_...Two coordination polymers, namely {[Mn(HL_1)(phen)]·4H_2O}_n(1) and [Co_2(HL_2)_2(H_2O)_2]_n(2) have been constructed hydrothermally using H_3L_1 and H_3L_2(H_3L_1 = 2-(5-carboxypyridin-2-yl)terephthalic acid, H_3L_2 = 2-(4-carboxypyridin-3-yl)terephthalic acid), phen, MnCl_2×4H_2O and CoCl_2×6H_2O. The products were isolated as stable crystalline solids and were characterized by IR spectroscopy, elemental, thermogravimetric(TGA), powder(PXRD) and single-crystal X-ray diffraction analyses. Compound 1 features a 3D framework structure, which was topologically classified as a trinodal 4,6,6-connected net with the unique topology defined by the point symbol of(3^(10).5.6~4)4(3^(10).6.7~4)2(5.6~2.8~2.9). Compound 2 possesses a 2D metal-organic layer, which was topologically classified as a binodal 4,4-connected layer defined by the point symbol of(4~3.6~2.8). The layers are further extended into a 3D supramolecular framework via hydrogen bonds. The magnetic properties for both compounds were also investigated, indicating antiferromagnetic interactions between the adjacent metal ions.展开更多
Under hydrothermal conditions, the reactions of Ni~Ⅱ/Cu~Ⅱ ions with 3-(6-aminpyridinium-3-yl) benzoate(HL) afford two compounds [NiL 2]n(1) and [Cu L2(H2 O)]n(2). On the basis of X-ray diffraction analysis of the tw...Under hydrothermal conditions, the reactions of Ni~Ⅱ/Cu~Ⅱ ions with 3-(6-aminpyridinium-3-yl) benzoate(HL) afford two compounds [NiL 2]n(1) and [Cu L2(H2 O)]n(2). On the basis of X-ray diffraction analysis of the two compounds, the results show that compound 1 features one-dimensional(1 D) double-strand coordination arrays, while 2 presents the 63-hcb layers. Both compounds are further constructed into a 3 D supramolecular structure with the aid of weak secondary interactions. Thermal stabilities and magnetic properties of compounds 1 and 2 were also investigated.展开更多
文摘It is a well-known fact that sirolimus(SRL) undergoes degradation process via hydrolysis in aqueous media, leading to incorrect assessment of drug amount and thus release characteristics of formulations.The main objective of the present study was to evaluate the effect of nonionic surfactants in media on invitro release profiles for sirolimus eluting stents(SES) coated with biodegradable polymeric matrix.Phosphate buffer and acetate buffer incorporating nonionic surfactants with varying concentrations were examined for adequate solubility and stability(by RP-HPLC). Good sink condition was achieved in phosphate buffer(at pH 4.0) with 1.0% Tween 20, 1.0% Brij 35% and 0.5% Brij 58. Hydrodynamic size(by DLS) and the micelle-water partition coefficient(P) with standard free energy of solubilization(ΔGs°) of drug were evaluated to get some understanding about the solubilization phenomena. About 80% of drug release during the period of 48 h was achieved in optimized drug release media which was 1.0% Tween20 in phosphate buffer pH 4.0. The obtained accelerated SRL release profile in optimized medium correlated well with the real time in-vitro release in phosphate buffer(pH 7.4). Surface morphology changes(by SEM), changes in gravimetric weights and molecular weight change(by GPC) were examined before and after drug release to understand the drug release mechanism which explains that the polymer did not undergo degradation during the drug release.
基金Financial support by the Major Scientific and Technological Projects of CNPC under Grant(No.ZD 2019-183-007)。
文摘The interfacial properties and rheological behavior of surfactant/polymer complex systems were measured to investigate the association behavior of the associating polymer.Compared with the pure surfactant solution,there are two inflection points in the surface tension curve for the surfactant/polymer complex systems.The two inflection points are dependent on the surfactant type and polymer concentration.The effect of surfactant on the rheological behavior of polymer can be divided into two aspects.First,the addition of short-chain betaine surfactant is detrimental to the viscosity of polymer solution due to the electrostatic shielding effect.Second,long-chain betaine surfactant also reduces the viscosity of polymer solutions at low concentrations.However,when the concentration of the long-chain betaine surfactant is relatively high,the long-chain betaine surfactant could form worm-like micelles that promote the intermolecular association and thus increase the number of associating junctions,thereby resulting in the augmentation of viscosity.So it is necessary to apply the long-chain betaine surfactant to build the polymer/surfactant flooding system.The interaction model between surfactant and polymer is proposed,which is different from the traditional‘Three-Region Model’.
基金the financial support provided by NSERC Discovery Grants to T. Babadagli (No: RES0011227) and H. Li (No. NSERC RGPIN 05394)。
文摘Nickel nanoparticles can work as catalyst for the aquathermolysis reactions between water and heavy oil.A homogeneous and stable suspension is needed to carry the nickel nanoparticles into deeper reservoirs.This study conducts a detailed investigation on how to achieve stabilized nickel nanoparticle suspensions with the use of surfactant and polymer.To stabilize the nickel nanoparticle suspension,three surfactants including sodium dodecyl sulfate,cationic surfactant cetyltrimethylammonium bromide and polyoxyalkalene amine derivative(Hypermer) along with xanthan gum polymer were introduced into the nickel nanoparticle suspension.Static stability tests and zeta potential measurements were conducted to determine the polymer/surfactant recipes yielding the most stable nickel nanoparticle suspensions.Dynamic micromodel flow tests were also conducted on three suspensions to reveal how the nickel nanoparticles would travel and distribute in porous media.Test results showed that when the injection was initiated,most nickel nanoparticles were able to pass through the gaps between the sand grains and produced in the outlet of the micromodel;only a small number of the nickel nanoparticles were attached to the grain surface.A higher nickel concentration in the suspension may lead to agglomeration of nickel nanoparticles in porous media,while a lower concentration can mitigate this agglomeration.Moreover,clusters tended to form when the nickel nanoparticle suspension carried an electrical charge opposite to that of the porous media.Follow-up waterflood was initiated after the nanofluid injection.It was found that the waterflood could not flush away the nanoparticles that were remaining in the micromodel.
基金Supported by China National Science and Technology Major Project(2016ZX05025-003-010) and (2016ZX05010-005).
文摘To understand the displacement characteristics and remaining oil displacement process by the surfactant/polymer(SP) flooding in cores with different pore structures, the effects of pore structure on the enhanced oil recovery of SP flooding was investigated at the pore, core and field scales through conducting experiments on natural core samples with three typical types of pore structures. First, the in-situ nuclear magnetic resonance core flooding test was carried out to capture the remaining oil variation features in the water flooding and SP flooding through these three types of cores. Subsequently, at the core scale, displacement characteristics and performances of water flooding and SP flooding in these three types of cores were evaluated based on the full-size core flooding tests. Finally, at the field scale, production characteristics of SP flooding in the bimodal sandstone reservoir and multimodal conglomerate reservoir were compared using the actual field production data. The results show: as the pore structure gets more and more complex, the water flooding performance gets poorer, but the incremental recovery factor by SP flooding gets higher;the SP flooding can enhance the producing degree of oil in 1-3 μm pores in the unimodal and bimodal core samples, while it produces largely oil in medium and large pores more than 3 μm in pore radius in the multimodal core sample. The core flooding test using full-size core sample demonstrates that the injection of SP solution can significantly raise up the displacement pressure of the multimodal core sample, and greatly enhance recovery factor by emulsifying the remaining oil and enlarging swept volume. Compared with the sandstone reservoir, the multimodal conglomerate reservoir is more prone to channeling. With proper profile control treatments to efficiently enlarge the microscopic and macroscopic swept volumes, SP flooding in the conglomerate reservoir can contribute to lower water cuts and longer effective durations.
基金Supported by the National Natural Science Foundation of China(Nos.20771030,20671025)
文摘Hollow calcium carbonate(CaCO3) microspheres with different morphologies were synthesized via the precipitation reaction of calcium chloride with sodium carbonate in the presence of different surfactant-polymer complexes.The selected anionic surfactants were sodium dodecyl sulfonate(SDS) and sodium dodecyl benzenesulfonate(SDBS),respectively.The selected water-soluble polymers were polyacrylic acid(PAA) and polyvinyl pyrrolidone(PVP).In this work,SDS-PVP "pearl-necklace model" micellar complex was formed via hydrophobic effectiveness between SDS and PVP and it served as the spherical template to generate spherical CaCO3 aggregates with hollow microspheres composed of about 500 nm irregular shaped particles.SDS-PAA complexes and SDBS-PAA complexes formed "core-shell model" aggregates with calcium ions serving as the medium to link the anionic surfactant and the polymer.SDS-PAA "core-shell model" aggregates would act as templates for hollow CaCO3 microspheres consisting of 30―50 nm irregular shaped crystallites.SDBS-PAA "core-shell model" aggregates served as the spherical aggregate templates to generate spherical CaCO3 aggregates consisted of many small spherical particles which had grown together.All the obtained CaCO3 hollow microspheres are calcite particles.This research may provide new insight into the control of morphologies of hollow CaCO3 microspheres in the presence of surfactantpolymer complexes.
文摘Orthogonal-test-design method has been used to determine the optimal formula by phase behavior and interfacial tension studies, respectively. The effect of each component of two alkaline/surfactant/polymer flooding systems on interfacial tension is discussed, in which a low-price natural mixed carboxylate (SDC) is used as the major surfactant. The results indicate that the optimal composition is SDC (0.5%), alkaline NaHCO3/Na2CO3 with mass ratio of 1 (1.0%), and hydrolyzed polyacrylamide(0.1%). In the coreflood experiment, their oil recovery is increased by about 25.2% and 26.8% original oil in place, respectively.
文摘By means of changing the detection angle, the molecular conformation of a new type of polymer surfactant, acrylamide-poly(oxyethykene alkyl ether)acrylate-anionic monomer random copolymer, was studied by x-ray photoelectron spectroscopy(XPS) in detail.
基金Project(2005CB221300) supported by the Major State Basic Research Development Program of China
文摘Based on deep analysis of ASP/oil emulsions flow behavior characteristic,a mathematical description of non-Newtonian emulsion was developed,and variation of rheological behaviors along the percolation flow direction was given.The effects of emulsions rheological behavior on oil recovery were quantity researched by a 2-D positive rhythm profile geological model.The result shows that the high viscosity and reduction of water phase permeability by emulsification can improve low-middle layer flow rate and enhance sweep efficiency,and the enhancement degree is related with emulsification degree.The study result can be used as reference for scheme design and production performance forecast during ASP flooding.
基金The financial support by the NSFC under Projects (Nos. 50533040, 20374033) is gratefully acknowledged.
文摘A surfactant-assisted method for preparing colloidal spheres with narrow size distribution from a polydispersed azo polymer has been developed in this work. The colloidal spheres were formed through gradual hydrophobic aggregation of the polymeric chains in THF-H2O dispersion media, which was induced by a steady increase in the water content. Results showed that the addition of a small amount of surfactant (SDBS) could significantly narrow the size distribution of the colloidal spheres. The size distribution of the colloidal spheres was determined by the concentrations of azo polymer and the amount of surfactant in the systems. When the concentrations of polymer and surfactant amount were in a proper range, colloidal spheres with narrow size distribution could be obtained. The colloidal spheres formed by this method could be elongated along the polarization direction of the laser beams upon Ar+ laser irradiation. The colloidal spheres are considered to be a new type of the colloid-based functional materials.
基金The National Key Research and Development Program of China(2021YFA1502000 and 2022YFA1505300)the National Natural Science Foundation of China (22288102, 22072124)+1 种基金support from Beijing Synchrotron Radiation Facility (1W1B, BSRF)China Scholarship Council for the financial support。
文摘With tunable local electronic environment,high mass density of MN4sites,and ease of preparation,metal-organic conjugated coordinative polymer(CCP) with inherent electronic conductivity provides a promising alternative to the well-known M-N-C electrocatalysts.Herein,the coordination reaction between Cu^(2+)and 1,2,4,5-tetraaminobenzene(TAB) was conducted on the surface of metallic Cu nanowires,forming a thin layer of CuN4-based CCP(Cu-TAB) on the Cu nanowire.More importantly,interfacial transfer of electrons from Cu core to the CuN4-based CCP nanoshell was observed within the resulting CuTAB@Cu,which was found to enrich the local electronic density of the CuN4sites.As such,the CuTAB@Cu demonstrates much improved affinity to the*COOH intermediate formed from the rate determining step;the energy barrier for C-C coupling,which is critical to convert CO_(2)into C2products,is also decreased.Accordingly,it delivers a current density of-9.1 mA cm^(-2)at a potential as high as 0.558 V(vs.RHE) in H-type cell and a Faraday efficiency of 46.4% for ethanol.This work emphasizes the profound role of interfacial interaction in tuning the local electronic structure and activating the CuN4-based CCPs for efficient electroreduction of CO_(2).
基金Project supported by the National Natural Science Foundation of China (No. 50578073)the Natural Science Foundation of Jiangsu Province, China (No. 2004088)the Major Projects of Environment Protection Office of Jiangsu Province, China (No. 2004001).
文摘Taking the pilot test area of polymer enhanced foam flooding in Y oilfield as the prototype, a numerical core model was established, and the polymer enhanced foam formulation system was optimized by analyzing the resistance factor and the change rule of oil recovery of different formulation systems. Research shows that the higher the polymer concentration, the greater the resistance factor, and the more obvious the sealing effect formed in the formation. The concentration of surfactant has a greater impact on the resistance factor. With the increase of surfactant concentration, the resistance factor increases significantly, and the plugging effect of foam agent on core is significantly enhanced. With the increase of gas-liquid ratio, the resistance factor first increases and then decreases. When the gas-liquid ratio is 1:1, the resistance is the largest, and the foam agent has the strongest plugging effect on the core. The optimal formula system of polymer enhanced foam flooding in Y oilfield is: polymer concentration is 1200 mg/L, surfactant concentration is 0.25 wt%, gas-liquid ratio is 1:1.
文摘A mixture of nine biphenyl nitrile compounds with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 min. The buffer system contained 100 mmol/L sodium dodecyl sulfate (SDS), 80 mmol/L sodium cholate (SC), 0.81% heptane, 7.5% n-butanol, 10% acetonitrile and 10 mmol/L borate. The addition of SC, organic modifiers, sample preparation and temperature all showed remarkable effect on the separation. Meanwhile, the MEEKC method was briefly compared with micellar electrokinetic chromatography (MEKC) method.
基金Funded in Part by the National Natural Science Foundation of China (No. 50878054)
文摘The objective of this research was to show a way to conduct rejuvenation of aged polymer modified asphalt binder(PMB) successfully.To fully evaluate and understand the rejuvenation of aged PMB,the Penetration grade tests including penetration,soften point,ductility and elastic recovery and SuperpaveTM PG grade tests including DSR,BBR and DDT were conducted.The rejuvenation effect of aged PMB by utilizing a fluid recycling agent in common use for binder rejuvenation was evaluated.And then the compound rejuvenation effect of aged PMB by utilizing the recycling agent with a new modifying additive for binder modification was evaluated.The experimental results indicated that the recycling agent in common use currently does not apply to polymer modified asphalt binder rejuvenation.But the recycling agent together with the modifying additive can restore the characteristics of aged polymer modified binder very well.Therefore,compound rejuvenation of polymer modified asphalt binder is recommended.
基金Programfor Changjiang Scholars and Innovative Research Teamin University (IRT0654)
文摘Polyester polyether block copolymer(PPBC) was synthesized by ester-exchange and polycondensation reactions using dimethyl terephthalate(DMT),ethylene glycol(EG) and polyethylene glycol(PEG) as monomer.The effects of PEG molecular weight,mol ratio of DMT to PEG(nDMT/nPEG),temperature and time of polycondensation reaction and vacuum degree in the reaction system on the surface tension and critical micelle concentration(CMC) of PPBC aqueous solution were studied.It was found that both the molecular weight and the concentration of PEG can affect PPBC's surface activity obviously,and the optimum synthesis condition of PPBC used as surfactant is as follows:PEG molecular weight is 1500,mol ratio of DMT to PEG is 3,temperature and time of polycondensation reaction is 260℃×1h,vacuum degree of condensation reaction is 0.03-0.05 MPa.It was proved by surface tension measurement of PPBC aqueous solution that the PPBC synthesized in this condition is a good surfactant with excellent surfactivity.
文摘The interaction of poly(ethylene oxide)(PEO)with the ionic surfactants,sodium dodecylsulfate(SDS)and cetyltrimethylammonium chloride(CTAC)respectively,in aqueous solutions containing a certain concentration of NH_4Cl, is studied by the viscosity measurement.It has been found that the ion-dipole interaction between PEO and ionic surfactants is changed considerably by the organic salt.For anionic suffactant of SDS,the addition of NH_4Cl into solution strengthens the interaction between PEO and the headgrou...
基金This work was supported by the grant of theted National Natural Science Foundation of China and by the Chinese Academy of Sciences.
文摘Three A-shaped nitropyrimidine derivatives with benzyl or furfuryl as bridge havebeen synthesized. They possess shorter absorption wavelengths (λ<sub>cut-off</sub>)【400 nm) andhigher βμ values (around 10<sup>-46</sup> esu). The second order nonlinear optical coefficient d<sub>33</sub> ofpoled BNPMOPMDA/PMMA doped film is 1.2-2.0×10<sup>-9</sup> esu obtained by in-situ SHGmeasurements. It can be expected that the chromophore-functionalized polymer containinghigher number density of synthesized chromophore as side chain will be the potential blue-light transparent frequency doubling materials.
基金Supported by Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2015)the Natural Science Foundation of Guangdong Province(No.2016A030313761)+3 种基金Science and Technology Planning Project of Guangzhou(No.201510010170)the Pearl River Scholar Foundation of Guangdong Industry Polytechnic(No.RC2015-001)the Opening Foundation of MOE Key Laboratory of Bioinorganic and Synthetic Chemistry School of Chemistry Sun Yat-Sen University(2016)National Natural Science Foundation of China(No.11272093)
文摘Two coordination polymers, namely {[Mn(HL_1)(phen)]·4H_2O}_n(1) and [Co_2(HL_2)_2(H_2O)_2]_n(2) have been constructed hydrothermally using H_3L_1 and H_3L_2(H_3L_1 = 2-(5-carboxypyridin-2-yl)terephthalic acid, H_3L_2 = 2-(4-carboxypyridin-3-yl)terephthalic acid), phen, MnCl_2×4H_2O and CoCl_2×6H_2O. The products were isolated as stable crystalline solids and were characterized by IR spectroscopy, elemental, thermogravimetric(TGA), powder(PXRD) and single-crystal X-ray diffraction analyses. Compound 1 features a 3D framework structure, which was topologically classified as a trinodal 4,6,6-connected net with the unique topology defined by the point symbol of(3^(10).5.6~4)4(3^(10).6.7~4)2(5.6~2.8~2.9). Compound 2 possesses a 2D metal-organic layer, which was topologically classified as a binodal 4,4-connected layer defined by the point symbol of(4~3.6~2.8). The layers are further extended into a 3D supramolecular framework via hydrogen bonds. The magnetic properties for both compounds were also investigated, indicating antiferromagnetic interactions between the adjacent metal ions.
基金supported by the National Natural Science Foundation of China(Nos.21671119,21301106 and 21673127)
文摘Under hydrothermal conditions, the reactions of Ni~Ⅱ/Cu~Ⅱ ions with 3-(6-aminpyridinium-3-yl) benzoate(HL) afford two compounds [NiL 2]n(1) and [Cu L2(H2 O)]n(2). On the basis of X-ray diffraction analysis of the two compounds, the results show that compound 1 features one-dimensional(1 D) double-strand coordination arrays, while 2 presents the 63-hcb layers. Both compounds are further constructed into a 3 D supramolecular structure with the aid of weak secondary interactions. Thermal stabilities and magnetic properties of compounds 1 and 2 were also investigated.