Aggregation of polyoxometalates(POM)is largely responsible for the reduced performance of POM-based energy-storage systems.To address this challenge,here,the precise confinement of single Keggin-type POM molecule in a...Aggregation of polyoxometalates(POM)is largely responsible for the reduced performance of POM-based energy-storage systems.To address this challenge,here,the precise confinement of single Keggin-type POM molecule in a porous carbon(PC)of unimodal super-micropore(micro-PC)is realized.Such precise single-molecule confinement enables sufficient activity center exposure and maximum electron-transfer from micro-PC to POM,which well stabilizes the electron-accepting molecules and thoroughly activates its inherent multi-electron redox-activity.In particular,the redox-activities and electron-accepting properties of the confined POM molecule are revealed to be super-micropore pore size-dependent by experiment and spectroscopy as well as theoretical calculation.Meanwhile,the molecularly dispersed POM molecules confined steadily in the“cage”of micro-PC exhibit unprecedented large-negative-potential stability and multiple-peak redox-activity at an ultra-low loading of~11.4 wt%.As a result,the fabricated solid-state supercapacitor achieves a remarkable areal capacitance,ultrahigh energy and power density of 443 mF cm^(-2),0.12 mWh cm^(-2)and 21.1 mW cm^(-2),respectively.This work establishes a novel strategy for the precise confinement of single POM molecule,providing a versatile approach to inducing the intrinsic activity of POMs for advanced energy-storage systems.展开更多
随着社会经济的快速发展,含氯有机物,特别是含氯苯系物,在农业、化工和医药等领域的使用量逐年增多,而使用过程中不合理的排放和控制致使含氯苯系物对生态环境,特别是水体环境的污染日趋严重.含氯苯系物具有高致毒致癌性,易生物富集,且...随着社会经济的快速发展,含氯有机物,特别是含氯苯系物,在农业、化工和医药等领域的使用量逐年增多,而使用过程中不合理的排放和控制致使含氯苯系物对生态环境,特别是水体环境的污染日趋严重.含氯苯系物具有高致毒致癌性,易生物富集,且很难被完全降解矿化,已被国家环保局认定为优先控制污染物.常规的废水处理工艺,如吸附、氧化及生物降解等,效率不高,且具有二次污染风险.电催化氢化脱氯技术是一种新型特别针对废水中含氯有机污染物的处理工艺,是通过在阴极电解还原水,原位生成原子态氢,以进攻苯环上C.Cl键,通过C.Cl键断裂H原子取代,使含氯苯系物完全转化为苯系物,达到去毒去害化的目的,近年来越来越受到研究者的关注.在整个电催化氢化脱氯技术中,高效稳定的电催化剂合成是关键,决定着脱氯效率、脱氯动力学、产物选择性及能量的利用率.本文报道了一种简易、无需添加任何表面活性剂的湿式还原法制备金属钯/氮化钛(Pd/TiN)和金属钯/碳(Pd/C)复合材料.在该复合材料中,金属钯颗粒具有均一的纳米尺寸(约5.0 nm)和球状形貌,且均匀分布在TiN和C载体上.作为针对水体中代表性含氯苯系物2,4-二氯苯酚的电催化氢化脱氯反应催化剂,Pd/TiN所展现的活性和稳定性均优于TiN和Pd/C,这源于TiN载体的促进作用.当TiN与Pd复合时,相应形成的Pd-TiN界面可改变Pd表面的电子结构,进一步优化Pd产活性氢及其吸附活化2,4-二氯苯酚的性能,因而其催化氢化脱氯活性增加.阴极工作电压是该催化反应中一个重要操作参数,决定了电催化氢化脱氯的效率和最终产物的构成.实验表明,.0.80 V vs Ag/AgCl是最佳操作电压,此时2,4-二氯苯酚的电催化氢化脱氯效率最高,可达到93.27%,且可实现最大程度的2,4-二氯苯酚向苯酚转化.脱氯反应路径研究发现,在Pd/TiN催化剂上2,4-二氯苯酚脱氯反应路径为2,4-二氯苯酚→对位一氯苯酚,邻位一氯苯酚→苯酚,但Pd/TiN对邻位和对位的C.Cl键断裂基本没有选择性.本文提供了一种新的有效调控Pd材料电催化氢化脱氯性能的方法,可望用于其他氢化反应体系的高效催化剂的设计合成,同时可推动电催化氢化脱氯技术在环境污染修复中的应用.展开更多
The flow behavior of gravity-driven falling film of non-conductive high viscosity polymer fluids on an industrial-scale vertical wavy wall was investigated in terms of film thickness and residence time distribution by...The flow behavior of gravity-driven falling film of non-conductive high viscosity polymer fluids on an industrial-scale vertical wavy wall was investigated in terms of film thickness and residence time distribution by numerical simulation and experiment.Falling film flow of high viscosity fluids was found to be steady on a vertical wavy wall in the presence of the large film thickness.The comparison between numerical simulation and experiment for the film thickness both in crest and trough of wavy wall showed good agreement.The simulation results of average residence time of falling film flow with different viscous fluids were also consistent with the experimental results.This work provides the initial insights of how to evaluate and optimize the falling film flow system of polymer fluid.展开更多
This paper addresses the problems of the robust stability and robust stabilization of a discrete-time system with polytopic uncertainties. A new and simple method is presented to directly decouple the Lyapunov matrix ...This paper addresses the problems of the robust stability and robust stabilization of a discrete-time system with polytopic uncertainties. A new and simple method is presented to directly decouple the Lyapunov matrix and the system dynamic matrix. Combining this method with the parameter-dependent Lyapunov function approach yields new criteria that include some existing ones as special cases. A numerical example illustrates the improvement over the existing ones.展开更多
The salt effect on the vaporliquid phase equilibrium(VLE)of solvent mixtures is of significant interest in the industrial production of 1,3,5trioxane.Experimental data for the VLE of quinary systems(formaldehyde+1,3,5...The salt effect on the vaporliquid phase equilibrium(VLE)of solvent mixtures is of significant interest in the industrial production of 1,3,5trioxane.Experimental data for the VLE of quinary systems(formaldehyde+1,3,5trioxane+methanol+salt+water)and their ternary subsystems(formaldehyde+salt+water),(1,3,5trioxane+salt+water),and(methanol+salt+water)were systematic measured under atmospheric pressure.The salts considered included KBr,NaNO_(3),and CaCl_(2).The extended UNIFAC model was used to describe the VLE of the saltcontaining reactive mixtures.The model parameters were determined from the experimental VLE data of ternary systems or obtained from the literature,and then were used to predict the VLE of systems(1,3,5trioxane+KBr+water),(methanol+KBr+water),(formaldehyde+KBr+water),and(formaldehyde+1,3,5trioxane+methanol+salt+water)with salt=KBr,NaNO_(3),and CaCl_(2).The predicted results showed good agreements with the measured results.Furthermore,the model was used to uncover the salt effect on the VLE of these multisolvent reactive systems.展开更多
This paper examines the delay-dependent H-infinity control problem for discrete-time linear systems with time-varying state delays and norm-bounded uncertainties. A new inequality for the finite sum of quadratic terms...This paper examines the delay-dependent H-infinity control problem for discrete-time linear systems with time-varying state delays and norm-bounded uncertainties. A new inequality for the finite sum of quadratic terms is first established. Then, some new delay-dependent criteria are derived by employing the new inequality to guarantee the robust stability of a closed-loop system with a prescribed H-infinity norm bound for all admissible uncertainties and bounded time-vary delays. A numerical example demonstrates that the proposed method is an improvement over existing ones.展开更多
Base on Prof. Maa Dah-You’s general theory of the microperforated-panel (MPP) absorber, We designed a noise reduction structure-sound attenuating cabinet (SAC). It can be applied to air-cooled communication products ...Base on Prof. Maa Dah-You’s general theory of the microperforated-panel (MPP) absorber, We designed a noise reduction structure-sound attenuating cabinet (SAC). It can be applied to air-cooled communication products to reduce system noise. This article introduces engineering design method of SAC and laboratory test noise reduction results of application of SAC.展开更多
With the rapid increase of lubricant consumption,oil contamination becomes more serious.Biotreatment is an important method to remove oil contamination with some advantages.In this study,acclimatized oilcontaminated s...With the rapid increase of lubricant consumption,oil contamination becomes more serious.Biotreatment is an important method to remove oil contamination with some advantages.In this study,acclimatized oilcontaminated soil and used lubricating oil were sampled to isolate lubricant-degrading strains by several methods.51 isolates were obtained and 24-well plates were employed to assess bacterial potential in highthroughput screening.The method was noted for the prominence of oil–water two-phase system with saving chemicals,shortening cycles and lessening workloads.In order to decrease inaccuracy,subculture and resting cells were inoculated into mineral salt medium with 200 μl oil in well plates for the cultivation at 37 °C for 5and 7 days,and the biodegradation potential was characterized by the changes of oil film and cell density.With appropriate evaluation by shaking flask tests,5 isolates were retained for their potentials with the maximum biodegradation from 1500 to 2200 mg · L^(-1)and identified as Acidovorax citrulli,Pseudomonas balearica,Acinetobacter johnsonii(two isolates with different biodegradation potentials)and Acidovorax avenae using 16 S r RNA sequencing analysis.Also,lipase activity was determined using indicator titration and p-nitrophenyl palmitate(p-NPP)methods.The results indicated that only p-NPP was successful to test lipase activity with the range of 1.93–6.29 U · ml^(-1).Although these five strains could degrade 1000 mg · L^(-1)lubricating oil in158–168 h,there existed distinct difference in enzyme activity,which demonstrates that lipase activity could not be used as the criterion to evaluate microbial biodegradation potential for petroleum hydrocarbons.展开更多
The extraction of linoleic acid from fatty acids(FA) of the cottonseed oil using starch–FA complexes was developed for the first time. We showed that starch can form inclusion complexes of different strengths with FA...The extraction of linoleic acid from fatty acids(FA) of the cottonseed oil using starch–FA complexes was developed for the first time. We showed that starch can form inclusion complexes of different strengths with FA and that the different strengths stem from the differences in chain length, degree of unsaturation, and position of double bonds of FA. The optimal separation conditions were determined as follows: The inclusion temperature is 69 °C, the inclusion time is 30 min, the starch/FA mass ratio is 10:1, and the ratio of the volume of methanol–water solution and the mass of FA is 18:1. Compared to urea inclusion complexation, starch complexation has milder reaction temperature and shorter reaction time. Under these conditions, linoleic acid can be concentrated from 38.9% to 70.04% by one-off extraction. Moreover, the experimental results demonstrate the almost perfect reusability of starch. These results show that starch complexation is a promising method that can be used to obtain highly concentrated linoleic acid from cottonseed oil.展开更多
This study focuses on the effect of chemical absorption on the formation dynamic characteristics and initial length of Taylor bubbles.The temporal evolutions of neck width and length of gaseous thread and initial leng...This study focuses on the effect of chemical absorption on the formation dynamic characteristics and initial length of Taylor bubbles.The temporal evolutions of neck width and length of gaseous thread and initial length with and without chemical absorption were investigated with the Capillary number and Hatta number between 0.0010–0.0073 and 1.8–5.8 respectively.The squeezing regime with typical three stages,expansion,squeezing and pinch off is observed for both two processes.Compared with the nonabsorption process,the increase of formation time in the chemical absorption process arises mainly from the expansion stage,and the decrease of initial length is from the necking stage.In addition,the temporal length evolution satisfies the power-law scale with the same exponent but a smaller pre-exponential factor.The correlations of neck width for stage transition and initial length with Hatta number demonstrate the enhancement effect of chemical absorption on bubble formation dynamics and initial length at relatively high chemical reaction rates and long formation time.This study provides insight into the bubble formation mechanism and helps to regulate the bubble initial size with chemical absorption.展开更多
Covalent organic frameworks(COFs) are a potential platform for carbon dioxide(CO_(2)) conversion owing to their periodic permanent porosity,adjustable structure,and chemical stability.For good catalytic performance in...Covalent organic frameworks(COFs) are a potential platform for carbon dioxide(CO_(2)) conversion owing to their periodic permanent porosity,adjustable structure,and chemical stability.For good catalytic performance in CO_(2) conversion,collaborative multifunctions should be strategically integrated into the catalytic system design and construction.In this study,a four-in-one high-efficiency catalyst was synthesized and tested for CO_(2) cycloaddition to form cyclic carbonate.The obtained Tp-MPB-BrCOF had a high nitrogen content,which enhanced its CO_(2) affinity through substantial Lewis acid-base or dipole-quadrupole interactions;moreover,the acid(protons transferring from oxygen(–OH) to nitrogen(–NH)),hydrogen bond donor(hydroxyl group),and Br-(nucleophile group) served as three active sites,further improving the catalyst activity.These results provide a basis for designing efficient and stable CO_(2)-conversion catalysts.展开更多
Implantable biomaterials are widely used in the curative resection and palliative treatment of various types of cancers.However,cancer residue around the implants usually leads to treatment failure with cancer reoccur...Implantable biomaterials are widely used in the curative resection and palliative treatment of various types of cancers.However,cancer residue around the implants usually leads to treatment failure with cancer reoccurrence.Postoperation chemotherapy and radiation therapy are widely applied to clear the residual cancer cells but induce serious side effects.It is urgent to develop advanced therapy to minimize systemic toxicity while maintaining efficient cancer-killing ability.Herein,we report a degenerate layered double hydroxide(LDH)film modified implant,which realizes microenvironment-responsive electrotherapy.The film can gradually transform into a nondegenerate state and release holes.When in contact with tumor cells or bacteria,the film quickly transforms into a nondegenerate state and releases holes at a high rate,rendering the“electrocution”of tumor cells and bacteria.However,when placed in normal tissue,the hole release rate of the film is much slower,thus,causing little harm to normal cells.Therefore,the constructed film can intelligently identify and meet the physiological requirements promptly.In addition,the transformation between degenerate and nondegenerate states of LDH films can be cycled by electrical charging,so their selective and dynamic physiological functions can be artificially adjusted according to demand.展开更多
Attempt of developing bio-safety and functional layered double hydroxides(LDHs)modifed plasma electrolytic oxidation(PEO)coatings,has become a hotspot in the protection of magnesium(Mg)based biomedical implants.In the...Attempt of developing bio-safety and functional layered double hydroxides(LDHs)modifed plasma electrolytic oxidation(PEO)coatings,has become a hotspot in the protection of magnesium(Mg)based biomedical implants.In the present work,Mg-Fe LDH flms with different Fe contents were fabricated on PEO coating via a novel two-step method:frstly,the Fe OOH flms were prepared by immersing PEO sample in Fe^(2+)-containing solution,and then Mg-Fe LDH flms were formed by transforming the Fe OOH flms via a hydrothermal treatment in water.The highly-oriented LDH nano-sheets could enhance the anti-corrosion performance of PEO coating,which was proved by the results of electrochemical test,hydrogen evolution and corroded morphology.PEO/Mg-Fe LDH coatings showed a low hemolysis rate(less5%)than PEO coating.In addition,PEO/Mg-Fe LDH coatings were more favorable for cell adhesion and proliferation than PEO coating.Moreover,PEO/Mg-Fe LDH coatings showed good photothermal conversion property,which demonstrated the excellent rapid antibacterial effect under NIR light.In vitro culture of rat bone marrow stem cell(r BMSC)suggested that cells cultured in the extract of PEO/Mg-Fe LDH coatings had a better osteogenic activity.In vivo subcutaneous implantation test revealed that PEO/Mg-Fe LDH coatings exhibited good anti-corrosion and histocompatibility.展开更多
Soft tissue sealing around implants acts as a barrier between the alveolar bone and oral environment,protecting implants from the invasion of bacteria or external stimuli.In this work,magnesium(Mg)and zinc(Zn)are intr...Soft tissue sealing around implants acts as a barrier between the alveolar bone and oral environment,protecting implants from the invasion of bacteria or external stimuli.In this work,magnesium(Mg)and zinc(Zn)are introduced into titanium by plasma immersed ion implantation technology,and their effects on the behaviors of human gingival fibroblasts(HGFs)as well as the underlying mechanisms are investigated.Surface characterization confirms Mg and Zn exist on the surface in metallic and oxidized states.Contact angle test suggests that surface wettability of titanium changes after ion implantation and thus influences protein adsorption of surfaces.In vitro studies disclose that HGFs on Mg ion-implanted samples exhibit better adhesion and migration while cells on Zn ion-implanted samples have higher proliferation rate and amounts.The results of immunofluorescence staining and real-time reverse-transcriptase polymerase chain reaction(RT-PCR)suggest that Mg mainly regulates the motility and adhesion of HGFs through activating the MAPK signal pathway whereas Zn influences HGFs proliferation by triggering the TGF-βsignal pathway.The synergistic effect of Mg and Zn ions ensure that HGFs cultured on co-implanted samples possessed both high proliferation rate and motility,which are critical to soft tissue sealing of implants.展开更多
基金the National Natural Science Foundation of China(No.51902222,5197222 and 62174013)
文摘Aggregation of polyoxometalates(POM)is largely responsible for the reduced performance of POM-based energy-storage systems.To address this challenge,here,the precise confinement of single Keggin-type POM molecule in a porous carbon(PC)of unimodal super-micropore(micro-PC)is realized.Such precise single-molecule confinement enables sufficient activity center exposure and maximum electron-transfer from micro-PC to POM,which well stabilizes the electron-accepting molecules and thoroughly activates its inherent multi-electron redox-activity.In particular,the redox-activities and electron-accepting properties of the confined POM molecule are revealed to be super-micropore pore size-dependent by experiment and spectroscopy as well as theoretical calculation.Meanwhile,the molecularly dispersed POM molecules confined steadily in the“cage”of micro-PC exhibit unprecedented large-negative-potential stability and multiple-peak redox-activity at an ultra-low loading of~11.4 wt%.As a result,the fabricated solid-state supercapacitor achieves a remarkable areal capacitance,ultrahigh energy and power density of 443 mF cm^(-2),0.12 mWh cm^(-2)and 21.1 mW cm^(-2),respectively.This work establishes a novel strategy for the precise confinement of single POM molecule,providing a versatile approach to inducing the intrinsic activity of POMs for advanced energy-storage systems.
基金supported by the National Natural Science Foundation of China(51508055,51502277)Chongqing Postdoctoral Science Foundation(Xm2016020)+2 种基金China Postdoctoral Science Foundation(2016M602660)Natural Science Foundation of Chongqing Science and Technology Commission(cstc2016jcyjA0154)Innovative Research Team of Chongqing(CXTDG201602014)~~
文摘随着社会经济的快速发展,含氯有机物,特别是含氯苯系物,在农业、化工和医药等领域的使用量逐年增多,而使用过程中不合理的排放和控制致使含氯苯系物对生态环境,特别是水体环境的污染日趋严重.含氯苯系物具有高致毒致癌性,易生物富集,且很难被完全降解矿化,已被国家环保局认定为优先控制污染物.常规的废水处理工艺,如吸附、氧化及生物降解等,效率不高,且具有二次污染风险.电催化氢化脱氯技术是一种新型特别针对废水中含氯有机污染物的处理工艺,是通过在阴极电解还原水,原位生成原子态氢,以进攻苯环上C.Cl键,通过C.Cl键断裂H原子取代,使含氯苯系物完全转化为苯系物,达到去毒去害化的目的,近年来越来越受到研究者的关注.在整个电催化氢化脱氯技术中,高效稳定的电催化剂合成是关键,决定着脱氯效率、脱氯动力学、产物选择性及能量的利用率.本文报道了一种简易、无需添加任何表面活性剂的湿式还原法制备金属钯/氮化钛(Pd/TiN)和金属钯/碳(Pd/C)复合材料.在该复合材料中,金属钯颗粒具有均一的纳米尺寸(约5.0 nm)和球状形貌,且均匀分布在TiN和C载体上.作为针对水体中代表性含氯苯系物2,4-二氯苯酚的电催化氢化脱氯反应催化剂,Pd/TiN所展现的活性和稳定性均优于TiN和Pd/C,这源于TiN载体的促进作用.当TiN与Pd复合时,相应形成的Pd-TiN界面可改变Pd表面的电子结构,进一步优化Pd产活性氢及其吸附活化2,4-二氯苯酚的性能,因而其催化氢化脱氯活性增加.阴极工作电压是该催化反应中一个重要操作参数,决定了电催化氢化脱氯的效率和最终产物的构成.实验表明,.0.80 V vs Ag/AgCl是最佳操作电压,此时2,4-二氯苯酚的电催化氢化脱氯效率最高,可达到93.27%,且可实现最大程度的2,4-二氯苯酚向苯酚转化.脱氯反应路径研究发现,在Pd/TiN催化剂上2,4-二氯苯酚脱氯反应路径为2,4-二氯苯酚→对位一氯苯酚,邻位一氯苯酚→苯酚,但Pd/TiN对邻位和对位的C.Cl键断裂基本没有选择性.本文提供了一种新的有效调控Pd材料电催化氢化脱氯性能的方法,可望用于其他氢化反应体系的高效催化剂的设计合成,同时可推动电催化氢化脱氯技术在环境污染修复中的应用.
基金Supported by the National Key Research and Development Program of China(2016YFB0303000)the National Natural Science Foundation of China(51803187)Zhejiang Provincial Natural Science Foundation of China(LQ18E030011)
文摘The flow behavior of gravity-driven falling film of non-conductive high viscosity polymer fluids on an industrial-scale vertical wavy wall was investigated in terms of film thickness and residence time distribution by numerical simulation and experiment.Falling film flow of high viscosity fluids was found to be steady on a vertical wavy wall in the presence of the large film thickness.The comparison between numerical simulation and experiment for the film thickness both in crest and trough of wavy wall showed good agreement.The simulation results of average residence time of falling film flow with different viscous fluids were also consistent with the experimental results.This work provides the initial insights of how to evaluate and optimize the falling film flow system of polymer fluid.
基金This work was supported in part by the Doctor Subject Foundation of China (No. 20050533015)the National Science Foundation of China(No. 60425310,60574014).
文摘This paper addresses the problems of the robust stability and robust stabilization of a discrete-time system with polytopic uncertainties. A new and simple method is presented to directly decouple the Lyapunov matrix and the system dynamic matrix. Combining this method with the parameter-dependent Lyapunov function approach yields new criteria that include some existing ones as special cases. A numerical example illustrates the improvement over the existing ones.
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation of China(grant numbers 22078355,21890763 and 21776300)Petrochemical Research Institute of PetroChina(grant number HX20200668)Scientific Research Project of Ordos Institute of Technology(grant numbers KYYB2019006).
文摘The salt effect on the vaporliquid phase equilibrium(VLE)of solvent mixtures is of significant interest in the industrial production of 1,3,5trioxane.Experimental data for the VLE of quinary systems(formaldehyde+1,3,5trioxane+methanol+salt+water)and their ternary subsystems(formaldehyde+salt+water),(1,3,5trioxane+salt+water),and(methanol+salt+water)were systematic measured under atmospheric pressure.The salts considered included KBr,NaNO_(3),and CaCl_(2).The extended UNIFAC model was used to describe the VLE of the saltcontaining reactive mixtures.The model parameters were determined from the experimental VLE data of ternary systems or obtained from the literature,and then were used to predict the VLE of systems(1,3,5trioxane+KBr+water),(methanol+KBr+water),(formaldehyde+KBr+water),and(formaldehyde+1,3,5trioxane+methanol+salt+water)with salt=KBr,NaNO_(3),and CaCl_(2).The predicted results showed good agreements with the measured results.Furthermore,the model was used to uncover the salt effect on the VLE of these multisolvent reactive systems.
基金This work was partially supported by the National Science Foundation of China (No. 60425310, 60574014), the Doctor Subject Foundation of China(No. 20050533015) and the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of the Ministryof Education, P. R. China (TRAPOYT).
文摘This paper examines the delay-dependent H-infinity control problem for discrete-time linear systems with time-varying state delays and norm-bounded uncertainties. A new inequality for the finite sum of quadratic terms is first established. Then, some new delay-dependent criteria are derived by employing the new inequality to guarantee the robust stability of a closed-loop system with a prescribed H-infinity norm bound for all admissible uncertainties and bounded time-vary delays. A numerical example demonstrates that the proposed method is an improvement over existing ones.
文摘Base on Prof. Maa Dah-You’s general theory of the microperforated-panel (MPP) absorber, We designed a noise reduction structure-sound attenuating cabinet (SAC). It can be applied to air-cooled communication products to reduce system noise. This article introduces engineering design method of SAC and laboratory test noise reduction results of application of SAC.
基金Supported by the National Natural Science Foundation of China(21376285)Chongqing Natural Science Foundation(CSTC2013jcyj A20014)+3 种基金Open Funding Project of the Key Laboratory of Systems BioengineeringMinistry of Educationand Scientific Platform ProjectMinistry of Education(FYKF201506)
文摘With the rapid increase of lubricant consumption,oil contamination becomes more serious.Biotreatment is an important method to remove oil contamination with some advantages.In this study,acclimatized oilcontaminated soil and used lubricating oil were sampled to isolate lubricant-degrading strains by several methods.51 isolates were obtained and 24-well plates were employed to assess bacterial potential in highthroughput screening.The method was noted for the prominence of oil–water two-phase system with saving chemicals,shortening cycles and lessening workloads.In order to decrease inaccuracy,subculture and resting cells were inoculated into mineral salt medium with 200 μl oil in well plates for the cultivation at 37 °C for 5and 7 days,and the biodegradation potential was characterized by the changes of oil film and cell density.With appropriate evaluation by shaking flask tests,5 isolates were retained for their potentials with the maximum biodegradation from 1500 to 2200 mg · L^(-1)and identified as Acidovorax citrulli,Pseudomonas balearica,Acinetobacter johnsonii(two isolates with different biodegradation potentials)and Acidovorax avenae using 16 S r RNA sequencing analysis.Also,lipase activity was determined using indicator titration and p-nitrophenyl palmitate(p-NPP)methods.The results indicated that only p-NPP was successful to test lipase activity with the range of 1.93–6.29 U · ml^(-1).Although these five strains could degrade 1000 mg · L^(-1)lubricating oil in158–168 h,there existed distinct difference in enzyme activity,which demonstrates that lipase activity could not be used as the criterion to evaluate microbial biodegradation potential for petroleum hydrocarbons.
基金Supported by the National Natural Science Foundation of China(21576285,21776300and 21276271)Innovation Foundation of China University of Petroleum,Beijing(ZX20160004)
文摘The extraction of linoleic acid from fatty acids(FA) of the cottonseed oil using starch–FA complexes was developed for the first time. We showed that starch can form inclusion complexes of different strengths with FA and that the different strengths stem from the differences in chain length, degree of unsaturation, and position of double bonds of FA. The optimal separation conditions were determined as follows: The inclusion temperature is 69 °C, the inclusion time is 30 min, the starch/FA mass ratio is 10:1, and the ratio of the volume of methanol–water solution and the mass of FA is 18:1. Compared to urea inclusion complexation, starch complexation has milder reaction temperature and shorter reaction time. Under these conditions, linoleic acid can be concentrated from 38.9% to 70.04% by one-off extraction. Moreover, the experimental results demonstrate the almost perfect reusability of starch. These results show that starch complexation is a promising method that can be used to obtain highly concentrated linoleic acid from cottonseed oil.
基金This study was supported by the National Natural Science Foundation of China(22008220,21776200,51973196)Natural Science Foundation of Zhejiang Province(LQ21B060009)the Key Research and Development Program of Zhejiang Province(2020C01010).
文摘This study focuses on the effect of chemical absorption on the formation dynamic characteristics and initial length of Taylor bubbles.The temporal evolutions of neck width and length of gaseous thread and initial length with and without chemical absorption were investigated with the Capillary number and Hatta number between 0.0010–0.0073 and 1.8–5.8 respectively.The squeezing regime with typical three stages,expansion,squeezing and pinch off is observed for both two processes.Compared with the nonabsorption process,the increase of formation time in the chemical absorption process arises mainly from the expansion stage,and the decrease of initial length is from the necking stage.In addition,the temporal length evolution satisfies the power-law scale with the same exponent but a smaller pre-exponential factor.The correlations of neck width for stage transition and initial length with Hatta number demonstrate the enhancement effect of chemical absorption on bubble formation dynamics and initial length at relatively high chemical reaction rates and long formation time.This study provides insight into the bubble formation mechanism and helps to regulate the bubble initial size with chemical absorption.
基金supported by the National Natural Science Foundation of China (21805173,52273208)Shanxi Agricultural University (SXBYKY2022078,2021BQ120)+1 种基金Shanxi Scholarship Council of China (2022-004)the Natural Science Foundation of Shanxi Province (202203021211289)。
文摘Covalent organic frameworks(COFs) are a potential platform for carbon dioxide(CO_(2)) conversion owing to their periodic permanent porosity,adjustable structure,and chemical stability.For good catalytic performance in CO_(2) conversion,collaborative multifunctions should be strategically integrated into the catalytic system design and construction.In this study,a four-in-one high-efficiency catalyst was synthesized and tested for CO_(2) cycloaddition to form cyclic carbonate.The obtained Tp-MPB-BrCOF had a high nitrogen content,which enhanced its CO_(2) affinity through substantial Lewis acid-base or dipole-quadrupole interactions;moreover,the acid(protons transferring from oxygen(–OH) to nitrogen(–NH)),hydrogen bond donor(hydroxyl group),and Br-(nucleophile group) served as three active sites,further improving the catalyst activity.These results provide a basis for designing efficient and stable CO_(2)-conversion catalysts.
基金support from the National Key R&D Program of China(2021YFC2400500)National Natural Science Foundation of China(31971249,51901239)+2 种基金Science and Technology Commission of Shanghai Municipality(19JC1415500,20S31903300)Natural Science Foundation of Hebei Province of China(E2021202001)High-level full-time talents project of Guangdong Provincial People’s Hospital(KY012021462).
文摘Implantable biomaterials are widely used in the curative resection and palliative treatment of various types of cancers.However,cancer residue around the implants usually leads to treatment failure with cancer reoccurrence.Postoperation chemotherapy and radiation therapy are widely applied to clear the residual cancer cells but induce serious side effects.It is urgent to develop advanced therapy to minimize systemic toxicity while maintaining efficient cancer-killing ability.Herein,we report a degenerate layered double hydroxide(LDH)film modified implant,which realizes microenvironment-responsive electrotherapy.The film can gradually transform into a nondegenerate state and release holes.When in contact with tumor cells or bacteria,the film quickly transforms into a nondegenerate state and releases holes at a high rate,rendering the“electrocution”of tumor cells and bacteria.However,when placed in normal tissue,the hole release rate of the film is much slower,thus,causing little harm to normal cells.Therefore,the constructed film can intelligently identify and meet the physiological requirements promptly.In addition,the transformation between degenerate and nondegenerate states of LDH films can be cycled by electrical charging,so their selective and dynamic physiological functions can be artificially adjusted according to demand.
基金fnancially supported by the National Key Research and Development Program of China(Nos.2017YFB0702600 and 2017YFB0702602)the National Natural Science Foundation of China(No.31771044)+1 种基金the Shanghai Committee of Science and Technology,China(Nos.20S31901200,18YF1426900 and 19JC1415500)the International Partnership Program of Chinese Academy of Sciences Grant(No.GJHZ1850)。
文摘Attempt of developing bio-safety and functional layered double hydroxides(LDHs)modifed plasma electrolytic oxidation(PEO)coatings,has become a hotspot in the protection of magnesium(Mg)based biomedical implants.In the present work,Mg-Fe LDH flms with different Fe contents were fabricated on PEO coating via a novel two-step method:frstly,the Fe OOH flms were prepared by immersing PEO sample in Fe^(2+)-containing solution,and then Mg-Fe LDH flms were formed by transforming the Fe OOH flms via a hydrothermal treatment in water.The highly-oriented LDH nano-sheets could enhance the anti-corrosion performance of PEO coating,which was proved by the results of electrochemical test,hydrogen evolution and corroded morphology.PEO/Mg-Fe LDH coatings showed a low hemolysis rate(less5%)than PEO coating.In addition,PEO/Mg-Fe LDH coatings were more favorable for cell adhesion and proliferation than PEO coating.Moreover,PEO/Mg-Fe LDH coatings showed good photothermal conversion property,which demonstrated the excellent rapid antibacterial effect under NIR light.In vitro culture of rat bone marrow stem cell(r BMSC)suggested that cells cultured in the extract of PEO/Mg-Fe LDH coatings had a better osteogenic activity.In vivo subcutaneous implantation test revealed that PEO/Mg-Fe LDH coatings exhibited good anti-corrosion and histocompatibility.
基金the National Natural Science Foundation of China(31971259,51831011,31870945)National Natural Science Foundation for Distinguished Young Scholars of China(51525207)+1 种基金Science and Technology Commission of Shanghai Municipality(18410760600,18YF1426900)International Partnership Program of Chinese Academy of Sciences(GJHZ1850)are acknowledged.
文摘Soft tissue sealing around implants acts as a barrier between the alveolar bone and oral environment,protecting implants from the invasion of bacteria or external stimuli.In this work,magnesium(Mg)and zinc(Zn)are introduced into titanium by plasma immersed ion implantation technology,and their effects on the behaviors of human gingival fibroblasts(HGFs)as well as the underlying mechanisms are investigated.Surface characterization confirms Mg and Zn exist on the surface in metallic and oxidized states.Contact angle test suggests that surface wettability of titanium changes after ion implantation and thus influences protein adsorption of surfaces.In vitro studies disclose that HGFs on Mg ion-implanted samples exhibit better adhesion and migration while cells on Zn ion-implanted samples have higher proliferation rate and amounts.The results of immunofluorescence staining and real-time reverse-transcriptase polymerase chain reaction(RT-PCR)suggest that Mg mainly regulates the motility and adhesion of HGFs through activating the MAPK signal pathway whereas Zn influences HGFs proliferation by triggering the TGF-βsignal pathway.The synergistic effect of Mg and Zn ions ensure that HGFs cultured on co-implanted samples possessed both high proliferation rate and motility,which are critical to soft tissue sealing of implants.