The construction of triplet-to-singlet F?rster resonance energy transfer(TS-FRET)systems has significantly contributed to the advancement of high-performance optoelectronic materials,particularly in the development of...The construction of triplet-to-singlet F?rster resonance energy transfer(TS-FRET)systems has significantly contributed to the advancement of high-performance optoelectronic materials,particularly in the development of metal-free organic environmental afterglow materials.Despite these notable advancements,achieving highly efficient energy transfer between luminescent donor and acceptor molecules remains a formidable challenge.In this study,we present the utilization of cation-πinteractions as an effective strategy to enhance TS-FRET efficiency,with the ultimate objective of further advancing fiuorescence afterglow materials.Our results demonstrate that the cation-πinteraction in 1D supramolecular nanorods(1D-SNRs)enhances the dipole-dipole coupling,a crucial parameter for regulating TS-FRET between the triplet state phosphorescent donor and singlet state fiuorescent acceptor.As a result,we achieved an outstanding TS-FRET efficiency of up to 97%.Furthermore,the 1D-SNRs exhibit a long-lifetime afterglow property,which suggests their potential application as a cost-effective and secure medium for information encryption.Thus,our findings highlight the promising prospects of cation-πinteractions in enhancing TS-FRET efficiency and advancing the field of organic photo-functional materials.展开更多
Herein, a low-cost, biodegradable, and high-performance microwave shielding graphite/starch material was fabricated via constructing a cation-π interaction between ammonium ions and graphite. The graphite flakes and ...Herein, a low-cost, biodegradable, and high-performance microwave shielding graphite/starch material was fabricated via constructing a cation-π interaction between ammonium ions and graphite. The graphite flakes and starch were firstly mixed with distilled water containing ammonium hydroxide to form graphite/starch slurry under an ultrasonic assistant. The cation-π interaction could improve delamination degree and dispersion of graphite in starch matrix. The slurry was first used as a coating material on the surface of wood and paper to develop shielding packages. The effect of coating thickness and coating layers on EM shielding property of the materials was investigated. Second, the composites with a high orientation of graphite were fabricated by compression at high pressures. The electrical conductivity and EM shielding effectiveness(SET) of the materials were greatly enhanced by construction of cation-πinteraction and orientation of graphite. Specifically, the EM SETvalues increased from 56.9 to 66.8 d B for the composites with 50 wt.% graphite and 2.0 mm in thickness by constructing cation-π interaction. The EM SETvalues raised from 17.4 to 66.8 d B via the graphite orientation in the materials with the same components and thickness. The shielding mechanism of the compressed composites with orientation dispersion of graphite was also discussed in comparison to the coating layer with random dispersion of graphite.展开更多
Reducing dietary cation-anion difference （DCAD） has been proved an effective way to prevent milk fever in dairy cows. Based on the similar physiological gastro-intestinal tract anatomy and metabolic process between ...Reducing dietary cation-anion difference （DCAD） has been proved an effective way to prevent milk fever in dairy cows. Based on the similar physiological gastro-intestinal tract anatomy and metabolic process between female goats and dairy cows, this study was conducted to evaluate the effects of varying DCAD on fluid acid-base status, plasma minerals concentration and anti-oxidative stress capacity of female goats. Urinary pH, plasma Ca, P and Mg; and anti-oxidative stress indices of total superoxide dismutase （T-SOD）, hydrogen peroxide （HzO2）, glutathione peroxidase （GSH-Px） and malondialdehyde （MDA） were determined to evaluate the effect. Forty-eight Guizhou black female goats （（15±1.9） mon of old, （22.3±3.75） kg of BW） were randomly allocated to 4 blocks of 12 goats each and were fed 1 of 4 diets differed in DCAD level （calculated as Na＋K-C1-S, mEq kg-1 DM）. Levels of DCAD were preliminarily designed to be control （＋ 150 mEq kg^-1 DM, CON）, high DCAD （＋300 mEq kg^-1 DM, HD）, low DCAD （0 mEq kg^-1 DM, LD） and negative DCAD （-150 mEq kg^-1 DM, ND）, respectively. A commercial anionic salts （Animate） and sodium bicarbonate （NaHCO3） were supplemented to reduce and increase DCAD level, respectively. There was no difference in dry matter intake for 4 groups of goats. Urine pH was aggressively decreased （P〈0.0001） with reduced DCAD and there was a strong association between DCAD and urine pH （R2=0.793, P〈0.0001）. Compared with CON and HD feeding of LD and ND resulted in greater （P〈0.05） plasma Ca concentration. Plasma P level was increased （P〈0.05） when anionic salts were supplemented. The DCAD alteration did not affected （P〉0.05） plasma Mg level. There was no significant （P〉0.05） difference in plasma GSH-Px activity and H202, but anionic salts supplementation in LD and ND significantly increased （P〈0.05） plasma T-SOD activity and tended to reduce MDA （P〈0.1） over HD and CON. Results from this study indicated that reducing DCAD could decrease urine pH and increase plasma Ca concentration of female goats. Additionally, reducing DCAD was helpful to enhance anti-oxidative stress capability of female goats.展开更多
The thermostability of some proteins in weak cation-exchange chromatography was investigated at 20-80 ℃. The results show that there is a fixed thermal denaturation transition temperature for each protein. The appear...The thermostability of some proteins in weak cation-exchange chromatography was investigated at 20-80 ℃. The results show that there is a fixed thermal denaturation transition temperature for each protein. The appearance of the thermal transition temperature indicates that the conformations of the proteins are destroyed seriously. The thermal behavior of the proteins in weak cation-exchange and hydrophobic interaction chromatographies were compared in a wide temperature range. It was found that the proteins have a higher thermostability in a weak cation-exchange chromatography system. The thermodynamic parameters(Δ H 0, Δ S 0) of those proteins were determined by means of Vant Hoff relationship(ln k -1/ T ). According to standard entropy change(Δ S 0), the conformational change of the proteins was judged in the chromatographic process. The linear relationships between Δ H 0 and Δ S 0 can be used to evaluate 'compensation temperature'( β ) at the protein denaturation and identify the identity of the protein retention mechanism in weak cation-exchange chromatography.展开更多
Using density functional theory computation, we show that sodium ions and hydrated sodium ions can be strongly adsorbed onto a hydrophobic graphite surface via cation-π interactions. The key to this eation-π interac...Using density functional theory computation, we show that sodium ions and hydrated sodium ions can be strongly adsorbed onto a hydrophobic graphite surface via cation-π interactions. The key to this eation-π interaction is the coupling of the delocalized π states of graphite and the empty orbitals of sodium ions. This finding implies that the property of the graphite surface is extremely dependent on the existence of the ions on the surface, suggesting that the hydrophobic property of the graphite surface may be affected by the existence of the sodium ions.展开更多
A sensitive method for the determination of ephedrine and codeine in human urine by capillary electrophoresis （CE） was described. In order to improve the sensitivity, two online concentration techniques including ca...A sensitive method for the determination of ephedrine and codeine in human urine by capillary electrophoresis （CE） was described. In order to improve the sensitivity, two online concentration techniques including cation-selective exhaustive injection （CSEI） and sweeping micellar electrokinetic chromatography （sweeping-MEKC） were used. Under the optimum conditions, the detection limits （S/N = 3） were 0.10 μg/L for ephedrine and 0.80 μg/L for codeine. This method was successfully applied to real urine sample analysis.展开更多
The retention mechanism of monocarboxylic acids on a cation-exchange resin column was investigated. It was assumed that both Donnan membrane equilibrium and adsorption equilibrium were involved in the chromatographic ...The retention mechanism of monocarboxylic acids on a cation-exchange resin column was investigated. It was assumed that both Donnan membrane equilibrium and adsorption equilibrium were involved in the chromatographic process. On the basis of the proposed mechanism, an equation was derived for correlating distribution coefficient, Kd, dissociation constant, Aa, and adsorption equilibrium constant, K, of the analyzed acid. By this approach, retention data for some aliphatic acids under different operating conditions were predicted. Results are reasonably in agreement with experiment.展开更多
An empirical solution to abnormal potential responses, showing peaks of emf, of commercial Cu2+- and Cd2+-selective electrodes with solid-state membranes was proposed for aqueous solutions of CuCl2 and CdI2. The two-s...An empirical solution to abnormal potential responses, showing peaks of emf, of commercial Cu2+- and Cd2+-selective electrodes with solid-state membranes was proposed for aqueous solutions of CuCl2 and CdI2. The two-step processes of Mn+ + Yn? (s: solid phase) MY(s) and MY(s) + 2X? X2MY2?(s) (n = 1, 2) at a test solution/electrode-interface were considered as a model. Here, Mn+, Yn?, and X? refer to a divalent or univalent cation, functional groups of electrode materials, and a halide ion (X? = Cl?, Br?, I?), respectively. By applying electrochemical potentials to these processes at n = 2, we derived an equation. Regression analyses based on the equation reproduced well the plots of emf versus log 2(*[M]t) for the Cd(II) and Cu(II) systems: *[M]t denotes a total concentration of species relevant to M2+ in a bulk of the aqueous solution. Also, we obtained log Ks(CdBr2) = 4.28 ? 0.22, log Ks(CdI2) = 6.98 ? 0.05, log Ks(CuCl2) = 3.96 ? 0.09, and log Ks(CuBr2) = 11.4 at 25?C. The magnitude in ?log Ks reflected that in the logarithmic solubility product, log {*[M2+](*[X?])2}, for bulk water, where *[M2+] or *[X?] denotes a molar concentration of the bulk solu-tion of M2+ or X? at equilibrium, respectively. Moreover, a mixture of CuSO4 with NaCl at the molar ratio of 1:1 yielded a plot similar to that of CuCl2.展开更多
In the present context, the objective of this study was to synthesize and analyze the content of AA of macadamia protein and the impact of hydrogen ion concentration (pH) on AA composition. The determination of AA mai...In the present context, the objective of this study was to synthesize and analyze the content of AA of macadamia protein and the impact of hydrogen ion concentration (pH) on AA composition. The determination of AA mainly by cation-exchange chromatography was also investigated. Reproducible and reliable techniques for quantification and identification of AA usually require derivatization. However, techniques such as AA analyzer are composed of cation-exchange chromatography and other components can sideline the derivatization with significant accuracy. The present analysis revealed a higher concentration of essential amino acids especially acidic AA, Glu and Asp and basic AA, Arg than other AA in macadamia protein. The study constitutes first report of use of bubble chart for evaluation of AA and explaination of AAS. The results may elaborate that the degradation of AA of macadamia protein for extraction of pH 11 is caused by the impact of pH. Moreover, the nutritional values of AA present in macadamia protein could change for the better by adjusting pH of extraction.展开更多
The diffusion permeability through new hybrid materials based on a Nafion-type membrane (MF- 4SC) and nanotubes of halloysite is investigated using the Nernst-Planck approach. A method of quantitative evaluation of ph...The diffusion permeability through new hybrid materials based on a Nafion-type membrane (MF- 4SC) and nanotubes of halloysite is investigated using the Nernst-Planck approach. A method of quantitative evaluation of physicochemical parameters (averaged and individual diffusion coefficients and averaged distribution coefficients of ion pairs in the membrane) of system “electrolyte solution—ion-exchange membrane—water”, which was proposed earlier, is further developed. The parameters of hybrid membranes on the base of MF-4SC and nanotubes of halloysite (5% wt and 8% wt) are obtained from experimental data on diffusion permeability of NaCl solutions using theoretical calculations. New model of three-layer membrane system can be used for refining calculated results with taking into account both diffusive layers. It is shown that adding of halloysite nanotubes into the membrane volume noticeably affects exchange capacity as well as structural and transport characteristics of original perfluorinated membranes. Hybrid membranes on the base of MF-4SC and halloysite nanotubes can be used in fuel cells and catalysis.展开更多
Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization,...Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization, and their indium adsorption properties were investigated. The synthesized PVGD and IPVGD resins were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury porosimetry. The cation-exchange capacity, the water uptake and the indium adsorption properties were investigated. The cation-exchange capacities of PVGD and IPVGD were 1.2 - 4.5 meq/g and 2.5 - 6.4 meq/g, respectively. The water uptakes were decreased with increasing contents of divinyl benzene (DVB). The water uptake values were 25% - 40% and 20% - 35%, respectively. The optimum adsorption of indium from a pure indium solution and an artificial indium tin oxide (ITO) solution by the PVGD and IPVGD ion-exchange resins were 2.3 and 3.5 meq/g, respectively. The indium adsorption capacities of IPVGD were higher than those of PVGD. The indium ion adsorption selectivity in the artificial ITO solution by PVGD and IPVGD was excellent, and other ions were adsorbed only slightly.展开更多
Achieving molecular self-assembly to produce functional supramolecular polymers with defined dimensions and structural periodicity is crucial,particularly for two-dimensional supramolecular polymers(2DSPs).However,a m...Achieving molecular self-assembly to produce functional supramolecular polymers with defined dimensions and structural periodicity is crucial,particularly for two-dimensional supramolecular polymers(2DSPs).However,a major challenge to their application has been poor electrical conductivity due to weakπ-electron delocalization in existing synthetic methods.Here,we overcome this limitation by demonstrating the controlled construction of conductive 2DSPs through self-aligned brick-like stacking of doubly chargedπ-conjugated monomers driven by aromatic cation-πinteractions.A key feature of this approach is the upright molecular orientation,a notable departure from the horizontal orientation typical of conventional 2D polymers.This versatile method is compatible with various molecular building blocks,enabling modulation of 2DSP conformation from flat to wavy.We have also prepared free-standing single-layer nanosheets of 2DSPs via solution-assisted exfoliation from their crystals.The resulting 2DSPs demonstrate efficient in-planeπ-electron delocalization,leading to impressive electrical conductivity properties,holding significant promise for optoelectronic applications.展开更多
The durable MXene-based electromagnetic interference(EMI)shielding film with flexible and good mechanical property is significantly desired for the rapid popularity of portable electronics,aerospace,and military.In th...The durable MXene-based electromagnetic interference(EMI)shielding film with flexible and good mechanical property is significantly desired for the rapid popularity of portable electronics,aerospace,and military.In this study,inspired by the supramolecular interactions in protein structures,we prepare the flexible MXene-based composite film by elaborately designing the cation-π interaction between arginine-modified MXene(AMXene)and tryptophan-modified epoxidized natural rubber.The resultant MXene-based composite film exhibits remarkable mechanical property.When the loading of A-MXene is only 8 wt.%,the tensile strength reaches 21.57 MPa,and the elongation at break is 880.06%.Moreover,the MXene-based composite film has satisfactory EMI shielding performance.Even after exposure to different conditions,including bending cycle of 7000 times,twisting cycle of 4000 times,ultrasonic treatment in water,soaking in water for 5 days,soaking in ethanol,treatment with HCl(pH=1),treatment with NaOH(pH=14),treatment with NaCl(3.5%),treatment at 200℃ for 2 h,treatment at -80℃ for 2 h,cyclic thermal shock,treatment at 85% relative humidity(RH)and 85℃ for 2 h,ultraviolet(UV)irradiation for 2 h,and storage at room temperature for 6 months,the EMI shielding efficiency of the film remains nearly unchanged,suggesting outstanding environmental durability.This work opens an avenue for the development of flexible,robust,and durable MXene-based EMI shielding film used in next-generation electronics.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22071197,22022107)Key Research Program of Frontier Sciences,CAS(No.QYZDJ-SSW-SLH044)+2 种基金Key Research Program of the Chinese Academy of Sciences,(No.XDPB01)Fundamental Research Funds for the Central Universities(No.D5000230114)China Postdoctoral Science Foundation(No.2023M730951)。
文摘The construction of triplet-to-singlet F?rster resonance energy transfer(TS-FRET)systems has significantly contributed to the advancement of high-performance optoelectronic materials,particularly in the development of metal-free organic environmental afterglow materials.Despite these notable advancements,achieving highly efficient energy transfer between luminescent donor and acceptor molecules remains a formidable challenge.In this study,we present the utilization of cation-πinteractions as an effective strategy to enhance TS-FRET efficiency,with the ultimate objective of further advancing fiuorescence afterglow materials.Our results demonstrate that the cation-πinteraction in 1D supramolecular nanorods(1D-SNRs)enhances the dipole-dipole coupling,a crucial parameter for regulating TS-FRET between the triplet state phosphorescent donor and singlet state fiuorescent acceptor.As a result,we achieved an outstanding TS-FRET efficiency of up to 97%.Furthermore,the 1D-SNRs exhibit a long-lifetime afterglow property,which suggests their potential application as a cost-effective and secure medium for information encryption.Thus,our findings highlight the promising prospects of cation-πinteractions in enhancing TS-FRET efficiency and advancing the field of organic photo-functional materials.
基金financially supported by the National Natural Science Foundation of China(No.52173264)the Natural Scienceof Chongqing(No.cstc2020jcyjmsxmX0401)。
文摘Herein, a low-cost, biodegradable, and high-performance microwave shielding graphite/starch material was fabricated via constructing a cation-π interaction between ammonium ions and graphite. The graphite flakes and starch were firstly mixed with distilled water containing ammonium hydroxide to form graphite/starch slurry under an ultrasonic assistant. The cation-π interaction could improve delamination degree and dispersion of graphite in starch matrix. The slurry was first used as a coating material on the surface of wood and paper to develop shielding packages. The effect of coating thickness and coating layers on EM shielding property of the materials was investigated. Second, the composites with a high orientation of graphite were fabricated by compression at high pressures. The electrical conductivity and EM shielding effectiveness(SET) of the materials were greatly enhanced by construction of cation-πinteraction and orientation of graphite. Specifically, the EM SETvalues increased from 56.9 to 66.8 d B for the composites with 50 wt.% graphite and 2.0 mm in thickness by constructing cation-π interaction. The EM SETvalues raised from 17.4 to 66.8 d B via the graphite orientation in the materials with the same components and thickness. The shielding mechanism of the compressed composites with orientation dispersion of graphite was also discussed in comparison to the coating layer with random dispersion of graphite.
基金funded by the National Natural Science Foundation of China (30901038, 31160468)the State Key Laboratory of Animal Nutrition, Ministry of Science and Technology, China (2004DA125184F1115)the Key Technology Research and Development Program of Guizhou Province, China ([2009]3085)
文摘Reducing dietary cation-anion difference （DCAD） has been proved an effective way to prevent milk fever in dairy cows. Based on the similar physiological gastro-intestinal tract anatomy and metabolic process between female goats and dairy cows, this study was conducted to evaluate the effects of varying DCAD on fluid acid-base status, plasma minerals concentration and anti-oxidative stress capacity of female goats. Urinary pH, plasma Ca, P and Mg; and anti-oxidative stress indices of total superoxide dismutase （T-SOD）, hydrogen peroxide （HzO2）, glutathione peroxidase （GSH-Px） and malondialdehyde （MDA） were determined to evaluate the effect. Forty-eight Guizhou black female goats （（15±1.9） mon of old, （22.3±3.75） kg of BW） were randomly allocated to 4 blocks of 12 goats each and were fed 1 of 4 diets differed in DCAD level （calculated as Na＋K-C1-S, mEq kg-1 DM）. Levels of DCAD were preliminarily designed to be control （＋ 150 mEq kg^-1 DM, CON）, high DCAD （＋300 mEq kg^-1 DM, HD）, low DCAD （0 mEq kg^-1 DM, LD） and negative DCAD （-150 mEq kg^-1 DM, ND）, respectively. A commercial anionic salts （Animate） and sodium bicarbonate （NaHCO3） were supplemented to reduce and increase DCAD level, respectively. There was no difference in dry matter intake for 4 groups of goats. Urine pH was aggressively decreased （P〈0.0001） with reduced DCAD and there was a strong association between DCAD and urine pH （R2=0.793, P〈0.0001）. Compared with CON and HD feeding of LD and ND resulted in greater （P〈0.05） plasma Ca concentration. Plasma P level was increased （P〈0.05） when anionic salts were supplemented. The DCAD alteration did not affected （P〉0.05） plasma Mg level. There was no significant （P〉0.05） difference in plasma GSH-Px activity and H202, but anionic salts supplementation in LD and ND significantly increased （P〈0.05） plasma T-SOD activity and tended to reduce MDA （P〈0.1） over HD and CON. Results from this study indicated that reducing DCAD could decrease urine pH and increase plasma Ca concentration of female goats. Additionally, reducing DCAD was helpful to enhance anti-oxidative stress capability of female goats.
基金Supported by Shaan xi Provincial Scientific- Comm ittee( 96 H0 9)
文摘The thermostability of some proteins in weak cation-exchange chromatography was investigated at 20-80 ℃. The results show that there is a fixed thermal denaturation transition temperature for each protein. The appearance of the thermal transition temperature indicates that the conformations of the proteins are destroyed seriously. The thermal behavior of the proteins in weak cation-exchange and hydrophobic interaction chromatographies were compared in a wide temperature range. It was found that the proteins have a higher thermostability in a weak cation-exchange chromatography system. The thermodynamic parameters(Δ H 0, Δ S 0) of those proteins were determined by means of Vant Hoff relationship(ln k -1/ T ). According to standard entropy change(Δ S 0), the conformational change of the proteins was judged in the chromatographic process. The linear relationships between Δ H 0 and Δ S 0 can be used to evaluate 'compensation temperature'( β ) at the protein denaturation and identify the identity of the protein retention mechanism in weak cation-exchange chromatography.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10674146 and 10825520)the National Basic Research Program of China (Grant No. 2007CB936000)the Knowledge Innovation Program of the Chinese Academy of Sciences
文摘Using density functional theory computation, we show that sodium ions and hydrated sodium ions can be strongly adsorbed onto a hydrophobic graphite surface via cation-π interactions. The key to this eation-π interaction is the coupling of the delocalized π states of graphite and the empty orbitals of sodium ions. This finding implies that the property of the graphite surface is extremely dependent on the existence of the ions on the surface, suggesting that the hydrophobic property of the graphite surface may be affected by the existence of the sodium ions.
基金supported by the Guangxi Provincial Foundation of Natural Science(No.0481019).
文摘A sensitive method for the determination of ephedrine and codeine in human urine by capillary electrophoresis （CE） was described. In order to improve the sensitivity, two online concentration techniques including cation-selective exhaustive injection （CSEI） and sweeping micellar electrokinetic chromatography （sweeping-MEKC） were used. Under the optimum conditions, the detection limits （S/N = 3） were 0.10 μg/L for ephedrine and 0.80 μg/L for codeine. This method was successfully applied to real urine sample analysis.
文摘The retention mechanism of monocarboxylic acids on a cation-exchange resin column was investigated. It was assumed that both Donnan membrane equilibrium and adsorption equilibrium were involved in the chromatographic process. On the basis of the proposed mechanism, an equation was derived for correlating distribution coefficient, Kd, dissociation constant, Aa, and adsorption equilibrium constant, K, of the analyzed acid. By this approach, retention data for some aliphatic acids under different operating conditions were predicted. Results are reasonably in agreement with experiment.
文摘An empirical solution to abnormal potential responses, showing peaks of emf, of commercial Cu2+- and Cd2+-selective electrodes with solid-state membranes was proposed for aqueous solutions of CuCl2 and CdI2. The two-step processes of Mn+ + Yn? (s: solid phase) MY(s) and MY(s) + 2X? X2MY2?(s) (n = 1, 2) at a test solution/electrode-interface were considered as a model. Here, Mn+, Yn?, and X? refer to a divalent or univalent cation, functional groups of electrode materials, and a halide ion (X? = Cl?, Br?, I?), respectively. By applying electrochemical potentials to these processes at n = 2, we derived an equation. Regression analyses based on the equation reproduced well the plots of emf versus log 2(*[M]t) for the Cd(II) and Cu(II) systems: *[M]t denotes a total concentration of species relevant to M2+ in a bulk of the aqueous solution. Also, we obtained log Ks(CdBr2) = 4.28 ? 0.22, log Ks(CdI2) = 6.98 ? 0.05, log Ks(CuCl2) = 3.96 ? 0.09, and log Ks(CuBr2) = 11.4 at 25?C. The magnitude in ?log Ks reflected that in the logarithmic solubility product, log {*[M2+](*[X?])2}, for bulk water, where *[M2+] or *[X?] denotes a molar concentration of the bulk solu-tion of M2+ or X? at equilibrium, respectively. Moreover, a mixture of CuSO4 with NaCl at the molar ratio of 1:1 yielded a plot similar to that of CuCl2.
文摘In the present context, the objective of this study was to synthesize and analyze the content of AA of macadamia protein and the impact of hydrogen ion concentration (pH) on AA composition. The determination of AA mainly by cation-exchange chromatography was also investigated. Reproducible and reliable techniques for quantification and identification of AA usually require derivatization. However, techniques such as AA analyzer are composed of cation-exchange chromatography and other components can sideline the derivatization with significant accuracy. The present analysis revealed a higher concentration of essential amino acids especially acidic AA, Glu and Asp and basic AA, Arg than other AA in macadamia protein. The study constitutes first report of use of bubble chart for evaluation of AA and explaination of AAS. The results may elaborate that the degradation of AA of macadamia protein for extraction of pH 11 is caused by the impact of pH. Moreover, the nutritional values of AA present in macadamia protein could change for the better by adjusting pH of extraction.
文摘The diffusion permeability through new hybrid materials based on a Nafion-type membrane (MF- 4SC) and nanotubes of halloysite is investigated using the Nernst-Planck approach. A method of quantitative evaluation of physicochemical parameters (averaged and individual diffusion coefficients and averaged distribution coefficients of ion pairs in the membrane) of system “electrolyte solution—ion-exchange membrane—water”, which was proposed earlier, is further developed. The parameters of hybrid membranes on the base of MF-4SC and nanotubes of halloysite (5% wt and 8% wt) are obtained from experimental data on diffusion permeability of NaCl solutions using theoretical calculations. New model of three-layer membrane system can be used for refining calculated results with taking into account both diffusive layers. It is shown that adding of halloysite nanotubes into the membrane volume noticeably affects exchange capacity as well as structural and transport characteristics of original perfluorinated membranes. Hybrid membranes on the base of MF-4SC and halloysite nanotubes can be used in fuel cells and catalysis.
文摘Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization, and their indium adsorption properties were investigated. The synthesized PVGD and IPVGD resins were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury porosimetry. The cation-exchange capacity, the water uptake and the indium adsorption properties were investigated. The cation-exchange capacities of PVGD and IPVGD were 1.2 - 4.5 meq/g and 2.5 - 6.4 meq/g, respectively. The water uptakes were decreased with increasing contents of divinyl benzene (DVB). The water uptake values were 25% - 40% and 20% - 35%, respectively. The optimum adsorption of indium from a pure indium solution and an artificial indium tin oxide (ITO) solution by the PVGD and IPVGD ion-exchange resins were 2.3 and 3.5 meq/g, respectively. The indium adsorption capacities of IPVGD were higher than those of PVGD. The indium ion adsorption selectivity in the artificial ITO solution by PVGD and IPVGD was excellent, and other ions were adsorbed only slightly.
基金supported by the National Natural Science Foundation of China(grant nos.22475171,22471219,22175142,22071197,22022107,22072103,51821002,and 22161132026)the Key Research and Development Program of Shaanxi(grant no.2024GX-YBXM-380)+1 种基金the Shaanxi Fundamental Science Research Project for Chemistry and Biology(grant nos.22JHQ019 and 23JHZ002)the Fundamental Research Funds for the Central Universities(grant nos.G2023KY0603 and D5000230114).
文摘Achieving molecular self-assembly to produce functional supramolecular polymers with defined dimensions and structural periodicity is crucial,particularly for two-dimensional supramolecular polymers(2DSPs).However,a major challenge to their application has been poor electrical conductivity due to weakπ-electron delocalization in existing synthetic methods.Here,we overcome this limitation by demonstrating the controlled construction of conductive 2DSPs through self-aligned brick-like stacking of doubly chargedπ-conjugated monomers driven by aromatic cation-πinteractions.A key feature of this approach is the upright molecular orientation,a notable departure from the horizontal orientation typical of conventional 2D polymers.This versatile method is compatible with various molecular building blocks,enabling modulation of 2DSP conformation from flat to wavy.We have also prepared free-standing single-layer nanosheets of 2DSPs via solution-assisted exfoliation from their crystals.The resulting 2DSPs demonstrate efficient in-planeπ-electron delocalization,leading to impressive electrical conductivity properties,holding significant promise for optoelectronic applications.
基金supported by the financial support from the National Natural Science Foundation of China(No.22006122)the Natural Science Foundation of Sichuan Province(No.2024NSFSC0291)the National Innovation and Entrepreneurship Training Program for College Students(No.202410619031).
文摘The durable MXene-based electromagnetic interference(EMI)shielding film with flexible and good mechanical property is significantly desired for the rapid popularity of portable electronics,aerospace,and military.In this study,inspired by the supramolecular interactions in protein structures,we prepare the flexible MXene-based composite film by elaborately designing the cation-π interaction between arginine-modified MXene(AMXene)and tryptophan-modified epoxidized natural rubber.The resultant MXene-based composite film exhibits remarkable mechanical property.When the loading of A-MXene is only 8 wt.%,the tensile strength reaches 21.57 MPa,and the elongation at break is 880.06%.Moreover,the MXene-based composite film has satisfactory EMI shielding performance.Even after exposure to different conditions,including bending cycle of 7000 times,twisting cycle of 4000 times,ultrasonic treatment in water,soaking in water for 5 days,soaking in ethanol,treatment with HCl(pH=1),treatment with NaOH(pH=14),treatment with NaCl(3.5%),treatment at 200℃ for 2 h,treatment at -80℃ for 2 h,cyclic thermal shock,treatment at 85% relative humidity(RH)and 85℃ for 2 h,ultraviolet(UV)irradiation for 2 h,and storage at room temperature for 6 months,the EMI shielding efficiency of the film remains nearly unchanged,suggesting outstanding environmental durability.This work opens an avenue for the development of flexible,robust,and durable MXene-based EMI shielding film used in next-generation electronics.
