Nano-silver loaded montmorillonite （Ag-MMT） was prepared by ion-exchange and then a UV-photoreduction two-step approach was applied. The silver content in Ag-MMT determined by Volhard method was about 6.4 wt%. The m...Nano-silver loaded montmorillonite （Ag-MMT） was prepared by ion-exchange and then a UV-photoreduction two-step approach was applied. The silver content in Ag-MMT determined by Volhard method was about 6.4 wt%. The morphology and structure of as-synthesized Ag-MMT were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results showed that the Ag nanoparticles were spherical and their diameters were about 15-20 nm. Moreover, the structure of MMT did not change. The minimum inhibition concentration （MIC） of Ag-MMT was 100×10-6 and the sterilizing efficiency （SE） of Ag-MMT was approximately 100% against Escherichia coli ATCC 11229 （E. coli. In addition, the slow release property of silver in Ag-MMT was also demonstrated.展开更多
Barium titanate(Ba TiO_(3)),a dielectric/ferroelectric semiconductor with perovskite structures is the most widely used photocatalyst in the field of environmental applications due to its low-cost,chemical stability,a...Barium titanate(Ba TiO_(3)),a dielectric/ferroelectric semiconductor with perovskite structures is the most widely used photocatalyst in the field of environmental applications due to its low-cost,chemical stability,and non-toxicity.Different types and forms of Ba TiO_(3)have shown their great potential toward the significant photocatalytic reactions owing to the several beneficial properties,including appropriate band positions,high oxygen vacancies,multiple crystal structures,the feasibility of size and morphology tailoring,spontaneous polarization,rapid migration of photogenerated charge carriers,and band bending.However,the large band gap and recombination of photogenerated charge carriers limit the overall photocatalytic efficiency of Ba TiO_(3).These difficulties can be further overcome by modifying the electronic band structure of Ba TiO_(3)to broaden its absorption to the visible region of the spectrum.Hence,this review encompasses various strategies,including modification of sizes and morphologies of particles by varying the reaction time and synthesis temperature,doping with non-metals/metals,loading with noble metals,and forming heterojunctions for enhancing the photocatalytic activities of Ba TiO_(3)-based photocatalysts possessing the effective capability of charge carrier separation,trapping and their transfer to the surface of photocatalyst.Also,this review highlights the photocatalytic applications of Ba TiO_(3)-based photocatalysts along with the proposed mechanism in dyes/drugs degradation,H_(2)production,and bacteria killing.展开更多
Friction and wear are unavoidable in mechanical movement.The use of lubricants with nano-additives can effectively reduce friction and wear,which is of great significance to saving energy and protecting the environmen...Friction and wear are unavoidable in mechanical movement.The use of lubricants with nano-additives can effectively reduce friction and wear,which is of great significance to saving energy and protecting the environment.At present,great progress has been made in the scientific research and industrial application of nano-additives for lubricants.This paper mainly introduces the types of nano-additives for lubricants(such as carbon nanomaterials,nano-metals,nano-oxides,sulfides,complexes,polymers,etc.),the tribological properties of lubricants with different components of nano-additives,and the lubrication mechanisms of the nano-additives(including tribofilm formation,rolling ball bearing effect,repairing effect,polishing effect,and synergistic effect).It also deals with the dispersion of nano-additives in lubricants and the influences of their particle size and microstructure on the tribological properties of lubricants.This review outlines the performance requirements of nano-additives in different lubrication states,discusses the use of nano-additives in challenging working conditions,and identifies various industrial oil nano-additives with reference to the appropriate options in diverse working environments.Furthermore,the existing problems of nano-additives and their application prospects are summarized.This review,hopefully,would help to shed light on the design and synthesis of novel high-performance nano-additives and promote their application in engineering.展开更多
Fecal bacteria contaminate water resources and result in associated waterborne diseases.This study assessed drinking water quality and evaluated their potential health risks in Swat, Pakistan. Ground and surface drink...Fecal bacteria contaminate water resources and result in associated waterborne diseases.This study assessed drinking water quality and evaluated their potential health risks in Swat, Pakistan. Ground and surface drinking water were randomly collected from upstream to downstream in the River Swat watershed and analyzed for fecal contamination using fecal indicator bacteria（Escherichia coli） and physiochemical parameters（potential of hydrogen, turbidity, temperature, electrical conductivity, total dissolved solid, color, odor and taste）. The physiochemical parameters were within their safe limits except in a few locations, whereas, the fecal contaminations in drinking water resources exceeded the drinking water quality standards of Pakistan Environmental Protection Agency（Pak-EPA）,2008 and World Health Organization（WHO）, 2011. Multivariate and univariate analyses revealed that downstream urbanization trend, minimum distance between water sources and pit latrines/sewerage systems, raw sewage deep well injection and amplified urban,pastures and agricultural runoffs having human and animal excreta were the possible sources of contamination. The questionnaire survey revealed that majority of the local people using 10–20 years old drinking water supply schemes at the rate of 73% well supply,13% hand pump supply, 11% spring supply and 3% river/streams supply, which spreads high prevalence of water borne diseases including hepatitis, intestinal infections and diarrhea, dysentery, cholera, typhoid fever, jaundice and skin diseases in children followed by older and younger adults.展开更多
CNT-added surface treatment (CAST) is a newly developed technology that incorporates single-walled carbon nanotubes (SWCNTs) into a metal surface through alternate current electrolysis using a dispersion of SWCNTs in ...CNT-added surface treatment (CAST) is a newly developed technology that incorporates single-walled carbon nanotubes (SWCNTs) into a metal surface through alternate current electrolysis using a dispersion of SWCNTs in an alkaline aqueous solution. We apply this method to Al-plates and characterize their surface morphology and components through scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. After CAST processing, protrusion structures of Al-oxide containing SWCNTs are formed on the surface of the Al-plate, and the surface morphology differs significantly from that of the surface of Al films treated through conventional anodic oxidation. The height and spacing of the protrusion structures formed on the surface of the CAST-treated Al-plates are 100 - 200 nm and 50 - 100 nm, respectively. In addition, we investigate the formation mechanism of the protrusion structure by applying a DC voltage between the working electrode (Al-plate) and a counter electrode immersed in a dispersion of SWCNTs in an alkaline aqueous solution. Comparing the Al-plate surface after treatment under both current directions, we propose a model for the formation process of protrusion structures containing SWCNTs based on catalyst surface etching.展开更多
Inorganic nanotubes of tungsten disulfide （INTs-WS2） are insoluble in common solvents and practically inert, hindering their usefulness in both research and commercial applications. The covalent attachment of functi...Inorganic nanotubes of tungsten disulfide （INTs-WS2） are insoluble in common solvents and practically inert, hindering their usefulness in both research and commercial applications. The covalent attachment of functional species onto the surface of INT-WS2 is a critical first step in realizing the potential that INT-WS2 offer for high-performance materials and products. Although a few attempts have been reported regarding preparing modified nanotubes, only a limited range of surface functionalities is possible with these methods. We have developed a versatile method, based on a modified, highly electrophilic acidic Vilsmeier- Haack reagent, to produce covalently bonded, polycarboxylated functional WS2 nanotubes that are dispersible in polar liquids, including water. The surface polycarboxylated shell provides a means for additional derivatization, enabling matching compatibility of derivatized nanotubes to both hydrophobic and hydrophilic materials. Nanocomposites incorporating derivatized INT-WS2 are expected to show improved properties as a result of enhanced interfacial compatibility, made possible by the large number of classes of functionalization available through the initial polycarboxylation step.展开更多
Chiral molecules are widely prevalent in nature and biological systems,and artificial chiral nanoparticles have drawn enormous interest owing to their unique optical and physical properties.However,nanoparticles with ...Chiral molecules are widely prevalent in nature and biological systems,and artificial chiral nanoparticles have drawn enormous interest owing to their unique optical and physical properties.However,nanoparticles with chiral morphologies and their potential role in biology have been rarely explored.Herein,we report a seed-mediated synthesis of enantiomorphic Au nanooctopods(NOPs)and their chiralmorphology dependence of cellular uptake.With a high yield(∼80%),the chiral NOPs possess eight uniform arms that bend from<111>to<100>directions,like a propeller structure.The chiral NOPs synthesized with L-or D-glutathione(GSH)have opposite handedness,resulting in opposite circular dichroism signals,which is consistent with finite-difference time-domain simulations.D-GSH NOPs demonstrate greater than 30%(ca.15%)enhanced cellular uptake in GL261 and bEnd.3 cells compared with L-GSH NOPs(racemic NOPs).Moreover,D-GSH NOPs modified with poly(ethylene glycol)or L-GSH are also preferred by the cells,proving the chiral-morphology dependence of cellular uptake.Our study develops the exploration of the chiral-specific interaction in biological systems,providing potential applications for drug delivery,biosensing,and tumor detection.展开更多
To obtain the optimal operating conditions of a coupled reactor for pyridine synthesis,reactor modeling process is carried out in this paper.During the modeling process,the flow hydrodynamics,heat transfer behavior,in...To obtain the optimal operating conditions of a coupled reactor for pyridine synthesis,reactor modeling process is carried out in this paper.During the modeling process,the flow hydrodynamics,heat transfer behavior,inter-phase mass transfer behavior and reaction kinetics were taken into consideration consequently.Further,a regression program based on least square method was proposed to regress the model parameters.The prediction results agreed well with the experimental results with an average deviation of 5.9%.Finally,by setting suitable aim function,the optimal operating conditions of the coupled reactor for pyridine synthesis were determined.展开更多
Phosphorus is one of the key elements,which determined the emergence of primordial life on our planet.The source of prebiotic phosphorus was most likely to be easily soluble compounds containing phosphorus in the nega...Phosphorus is one of the key elements,which determined the emergence of primordial life on our planet.The source of prebiotic phosphorus was most likely to be easily soluble compounds containing phosphorus in the negative form of oxidation(e.g.,phosphides).The present paper is the first thorough investigation of phosphide-bearing mineral assemblages confined to telluric(terrestrial)native iron from volcanic rocks of Disko Island,Greenland.Phosphorus speciation in given assemblages varies from the solid solution in native iron(up to 0.3 wt.%P),different phosphides–schreibersite Fe_(3)P,nickelphosphide Ni_(3)P,barringerite Fe_(2)P,and phosphates,including fluorapatite,anhydrous Fe-Na phosphates,phosphoran olivine and pyroxene(up to 1 wt.%P).The diversity of observed phosphorus speciation can be explained by the steep changes of redox conditions during subsurface crystallization of iron-phosphide-bearing lavas.Based on the available data on likely redox conditions on the early Earth,we hypothesize that reactive prebiotic phosphorus may have originated from shallow crustal rocks.展开更多
A material-structure integrated design method is proposed in this paper,with which micropillar and microwedge arrayed surfaces are fabricated based on a novel nanoparticlereinforced silicone rubber composite(NRSRC)wit...A material-structure integrated design method is proposed in this paper,with which micropillar and microwedge arrayed surfaces are fabricated based on a novel nanoparticlereinforced silicone rubber composite(NRSRC)with high mechanical strength and strong surface adhesion.It is found that the micropillar-arrayed surface and the microwedgearrayed surface show a normal adhesive strength of 50.9 kPa and a shear adhesive strength of 137.3 kPa,respectively,which are much higher than those of previously reported adhesive surfaces made by pure soft polymers.Furthermore,the micro-wedgearrayed surface shows not only strong and stable adhe-sion on rough and smooth substrates but also an obvious anisotropy in the adhesion property.The latter consequently leads to an easy control of the attachment/detachment switch,which is evidenced by a mechanical gripper with a microwedged surface.Therefore,firmly picking up and easily releasing a heavy glass plate can be realized.All these results demonstrate the apparent advantages of the present compo-sitebased fibrillar surfaces in achieving reliable and reversible adhesion and should have promising applications for manufac-turing advanced adhesive devices,such as mechanical fixtures,portable climbing equipment and space robots.展开更多
基金Huazhong University of Science and Technology,China, for the analytical support
文摘Nano-silver loaded montmorillonite （Ag-MMT） was prepared by ion-exchange and then a UV-photoreduction two-step approach was applied. The silver content in Ag-MMT determined by Volhard method was about 6.4 wt%. The morphology and structure of as-synthesized Ag-MMT were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results showed that the Ag nanoparticles were spherical and their diameters were about 15-20 nm. Moreover, the structure of MMT did not change. The minimum inhibition concentration （MIC） of Ag-MMT was 100×10-6 and the sterilizing efficiency （SE） of Ag-MMT was approximately 100% against Escherichia coli ATCC 11229 （E. coli. In addition, the slow release property of silver in Ag-MMT was also demonstrated.
基金supported by the Traditional Culture Convergence Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT and Future Planning(2018M3C1B5052283)supported by the National Research Foundation of Korea(NRF)grant funded by the Korea Government(MSIT)(No.NRF2019R1A2C1004467)。
文摘Barium titanate(Ba TiO_(3)),a dielectric/ferroelectric semiconductor with perovskite structures is the most widely used photocatalyst in the field of environmental applications due to its low-cost,chemical stability,and non-toxicity.Different types and forms of Ba TiO_(3)have shown their great potential toward the significant photocatalytic reactions owing to the several beneficial properties,including appropriate band positions,high oxygen vacancies,multiple crystal structures,the feasibility of size and morphology tailoring,spontaneous polarization,rapid migration of photogenerated charge carriers,and band bending.However,the large band gap and recombination of photogenerated charge carriers limit the overall photocatalytic efficiency of Ba TiO_(3).These difficulties can be further overcome by modifying the electronic band structure of Ba TiO_(3)to broaden its absorption to the visible region of the spectrum.Hence,this review encompasses various strategies,including modification of sizes and morphologies of particles by varying the reaction time and synthesis temperature,doping with non-metals/metals,loading with noble metals,and forming heterojunctions for enhancing the photocatalytic activities of Ba TiO_(3)-based photocatalysts possessing the effective capability of charge carrier separation,trapping and their transfer to the surface of photocatalyst.Also,this review highlights the photocatalytic applications of Ba TiO_(3)-based photocatalysts along with the proposed mechanism in dyes/drugs degradation,H_(2)production,and bacteria killing.
基金National Natural Science Foundation of China(21805085)The Key Technologies R&D Program of Henan Province(212102210039)+2 种基金Scientific and Technological Innovation Team of Henan Province University(22IRTSTHN018)Zhongyuan Science and Technology Innovation Leadership Program(214200510024)Visiting Professor Fund Project of North China University of Water Resources and Electric Power(4001-40734).
文摘Friction and wear are unavoidable in mechanical movement.The use of lubricants with nano-additives can effectively reduce friction and wear,which is of great significance to saving energy and protecting the environment.At present,great progress has been made in the scientific research and industrial application of nano-additives for lubricants.This paper mainly introduces the types of nano-additives for lubricants(such as carbon nanomaterials,nano-metals,nano-oxides,sulfides,complexes,polymers,etc.),the tribological properties of lubricants with different components of nano-additives,and the lubrication mechanisms of the nano-additives(including tribofilm formation,rolling ball bearing effect,repairing effect,polishing effect,and synergistic effect).It also deals with the dispersion of nano-additives in lubricants and the influences of their particle size and microstructure on the tribological properties of lubricants.This review outlines the performance requirements of nano-additives in different lubrication states,discusses the use of nano-additives in challenging working conditions,and identifies various industrial oil nano-additives with reference to the appropriate options in diverse working environments.Furthermore,the existing problems of nano-additives and their application prospects are summarized.This review,hopefully,would help to shed light on the design and synthesis of novel high-performance nano-additives and promote their application in engineering.
基金supported by the National Key R&D Program of China(No.2017YFC0505704)the National Natural Science Foundation of China(Nos.41420104004 and 71761147001)+3 种基金the Key Project of the Chinese Academy of Sciences(No.KFZDSW-322)the Key Technology R&D Program of Tianjin(No.16YFXTSF00380)the Chinese Academy of Sciences(CAS)President's International Fellowship Initiative(PIFI)
文摘Fecal bacteria contaminate water resources and result in associated waterborne diseases.This study assessed drinking water quality and evaluated their potential health risks in Swat, Pakistan. Ground and surface drinking water were randomly collected from upstream to downstream in the River Swat watershed and analyzed for fecal contamination using fecal indicator bacteria（Escherichia coli） and physiochemical parameters（potential of hydrogen, turbidity, temperature, electrical conductivity, total dissolved solid, color, odor and taste）. The physiochemical parameters were within their safe limits except in a few locations, whereas, the fecal contaminations in drinking water resources exceeded the drinking water quality standards of Pakistan Environmental Protection Agency（Pak-EPA）,2008 and World Health Organization（WHO）, 2011. Multivariate and univariate analyses revealed that downstream urbanization trend, minimum distance between water sources and pit latrines/sewerage systems, raw sewage deep well injection and amplified urban,pastures and agricultural runoffs having human and animal excreta were the possible sources of contamination. The questionnaire survey revealed that majority of the local people using 10–20 years old drinking water supply schemes at the rate of 73% well supply,13% hand pump supply, 11% spring supply and 3% river/streams supply, which spreads high prevalence of water borne diseases including hepatitis, intestinal infections and diarrhea, dysentery, cholera, typhoid fever, jaundice and skin diseases in children followed by older and younger adults.
文摘CNT-added surface treatment (CAST) is a newly developed technology that incorporates single-walled carbon nanotubes (SWCNTs) into a metal surface through alternate current electrolysis using a dispersion of SWCNTs in an alkaline aqueous solution. We apply this method to Al-plates and characterize their surface morphology and components through scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. After CAST processing, protrusion structures of Al-oxide containing SWCNTs are formed on the surface of the Al-plate, and the surface morphology differs significantly from that of the surface of Al films treated through conventional anodic oxidation. The height and spacing of the protrusion structures formed on the surface of the CAST-treated Al-plates are 100 - 200 nm and 50 - 100 nm, respectively. In addition, we investigate the formation mechanism of the protrusion structure by applying a DC voltage between the working electrode (Al-plate) and a counter electrode immersed in a dispersion of SWCNTs in an alkaline aqueous solution. Comparing the Al-plate surface after treatment under both current directions, we propose a model for the formation process of protrusion structures containing SWCNTs based on catalyst surface etching.
文摘Inorganic nanotubes of tungsten disulfide （INTs-WS2） are insoluble in common solvents and practically inert, hindering their usefulness in both research and commercial applications. The covalent attachment of functional species onto the surface of INT-WS2 is a critical first step in realizing the potential that INT-WS2 offer for high-performance materials and products. Although a few attempts have been reported regarding preparing modified nanotubes, only a limited range of surface functionalities is possible with these methods. We have developed a versatile method, based on a modified, highly electrophilic acidic Vilsmeier- Haack reagent, to produce covalently bonded, polycarboxylated functional WS2 nanotubes that are dispersible in polar liquids, including water. The surface polycarboxylated shell provides a means for additional derivatization, enabling matching compatibility of derivatized nanotubes to both hydrophobic and hydrophilic materials. Nanocomposites incorporating derivatized INT-WS2 are expected to show improved properties as a result of enhanced interfacial compatibility, made possible by the large number of classes of functionalization available through the initial polycarboxylation step.
基金K.L.thanks the National Natural Science Foundation of China(nos.21674042,21975094,21911530179,and 21534004)for financial support.K.L.T.S.thank the Interdisciplinary Innovation Project of the First Hospital of Jilin University(no.JDYYJCHX001)supported by the Program for JLU Science and Technology Innovative Research Team“JLUS-TIRT2017TD-06”.
文摘Chiral molecules are widely prevalent in nature and biological systems,and artificial chiral nanoparticles have drawn enormous interest owing to their unique optical and physical properties.However,nanoparticles with chiral morphologies and their potential role in biology have been rarely explored.Herein,we report a seed-mediated synthesis of enantiomorphic Au nanooctopods(NOPs)and their chiralmorphology dependence of cellular uptake.With a high yield(∼80%),the chiral NOPs possess eight uniform arms that bend from<111>to<100>directions,like a propeller structure.The chiral NOPs synthesized with L-or D-glutathione(GSH)have opposite handedness,resulting in opposite circular dichroism signals,which is consistent with finite-difference time-domain simulations.D-GSH NOPs demonstrate greater than 30%(ca.15%)enhanced cellular uptake in GL261 and bEnd.3 cells compared with L-GSH NOPs(racemic NOPs).Moreover,D-GSH NOPs modified with poly(ethylene glycol)or L-GSH are also preferred by the cells,proving the chiral-morphology dependence of cellular uptake.Our study develops the exploration of the chiral-specific interaction in biological systems,providing potential applications for drug delivery,biosensing,and tumor detection.
基金supports from the Natural Science Foundation of Henan(grant No.202300410063)the National Natural Science Foundation of China(grant Nos.91834303,21961132026)+1 种基金the First-class Discipline Construction Project of Henan University(grant No.2019YLZDCG01)the interdisciplinary Research for First-class Discipline Construction Project of Henan University(grant No.2019 YLXKJC04).
文摘To obtain the optimal operating conditions of a coupled reactor for pyridine synthesis,reactor modeling process is carried out in this paper.During the modeling process,the flow hydrodynamics,heat transfer behavior,inter-phase mass transfer behavior and reaction kinetics were taken into consideration consequently.Further,a regression program based on least square method was proposed to regress the model parameters.The prediction results agreed well with the experimental results with an average deviation of 5.9%.Finally,by setting suitable aim function,the optimal operating conditions of the coupled reactor for pyridine synthesis were determined.
基金supported by the Russian Science Foundation(grant 23-77-10025).
文摘Phosphorus is one of the key elements,which determined the emergence of primordial life on our planet.The source of prebiotic phosphorus was most likely to be easily soluble compounds containing phosphorus in the negative form of oxidation(e.g.,phosphides).The present paper is the first thorough investigation of phosphide-bearing mineral assemblages confined to telluric(terrestrial)native iron from volcanic rocks of Disko Island,Greenland.Phosphorus speciation in given assemblages varies from the solid solution in native iron(up to 0.3 wt.%P),different phosphides–schreibersite Fe_(3)P,nickelphosphide Ni_(3)P,barringerite Fe_(2)P,and phosphates,including fluorapatite,anhydrous Fe-Na phosphates,phosphoran olivine and pyroxene(up to 1 wt.%P).The diversity of observed phosphorus speciation can be explained by the steep changes of redox conditions during subsurface crystallization of iron-phosphide-bearing lavas.Based on the available data on likely redox conditions on the early Earth,we hypothesize that reactive prebiotic phosphorus may have originated from shallow crustal rocks.
基金NSFC through Grants(No.12032004,No.12293000,No.12293002,No.12272043)Natural Science Foundation of Henan(No.202300410088)as well as Innovation Demonstration Project of Henan(No.201111211400).
文摘A material-structure integrated design method is proposed in this paper,with which micropillar and microwedge arrayed surfaces are fabricated based on a novel nanoparticlereinforced silicone rubber composite(NRSRC)with high mechanical strength and strong surface adhesion.It is found that the micropillar-arrayed surface and the microwedgearrayed surface show a normal adhesive strength of 50.9 kPa and a shear adhesive strength of 137.3 kPa,respectively,which are much higher than those of previously reported adhesive surfaces made by pure soft polymers.Furthermore,the micro-wedgearrayed surface shows not only strong and stable adhe-sion on rough and smooth substrates but also an obvious anisotropy in the adhesion property.The latter consequently leads to an easy control of the attachment/detachment switch,which is evidenced by a mechanical gripper with a microwedged surface.Therefore,firmly picking up and easily releasing a heavy glass plate can be realized.All these results demonstrate the apparent advantages of the present compo-sitebased fibrillar surfaces in achieving reliable and reversible adhesion and should have promising applications for manufac-turing advanced adhesive devices,such as mechanical fixtures,portable climbing equipment and space robots.
