Lubricants have played important roles in friction and wear reduction and increasing efficiency of mechanical systems.To optimize tribological performance,chemical reactions between a lubricant and a substrate must be...Lubricants have played important roles in friction and wear reduction and increasing efficiency of mechanical systems.To optimize tribological performance,chemical reactions between a lubricant and a substrate must be designed strategically.Tribochemical reactions are chemical reactions enabled or accelerated by mechanical stimuli.Tribochemically activated lubricant additives play important roles in these reactions.In this review,current understanding in mechanisms of chemical reactions under shear has been discussed.Additives such as oil-soluble organics,ionic liquids(ILs),and nanoparticles(NPs)were analyzed in relation to the tribochemical reaction routes with elements in metallic substrates.The results indicated that phosphorus,sulfur,fluorine,and nitrogen are key elements for tribochemical reactions.The resulting tribofilms from zinc dithiophosphates(ZDDP)and molybdenum dithiocarbamate(MoDTC)have been widely reported,yet that from ILs and NPs need to investigate further.This review serves as a reference for researchers to design and optimize new lubricants.展开更多
Controlled integration of ultrafine metal nanoparticles （MNPs） and metal- organic frameworks （MOFs） has drawn much attention due to their unique physical and chemical properties. However, the development of a one-...Controlled integration of ultrafine metal nanoparticles （MNPs） and metal- organic frameworks （MOFs） has drawn much attention due to their unique physical and chemical properties. However, the development of a one-step strategy for preparing ultrafine MNPs within MOFs still remains a great challenge. Herein, a facile synthetic approach toward the abovementioned composites was developed. In contrast to the conventional approach, these hybrids were prepared by the direct mixing of metal and MOF precursors in the reaction solution assisted by microwave irradiation. Impressively, the Au/MOF-199 composite with uniformly distributed ultrafine Au nanoparticles could be fabricated in only two minutes, and the Au loading could be increased up to a level of 5.13%. The multifunctional Au/MOF-199 catalysts exhibited high turnover numbers （TONs） and turnover frequencies （TOFs） in the three-component coupling reaction of formaldehyde, phenylacetylene, and piperidine （AB-coupling）. Owing to the confinement effect of MOF-199, the 5.13%Au/MOF-199 catalyst could be recycled for five runs without serious loss of activity, with no obvious aggregation of Au NPs detected.展开更多
The development of low-cost,stable,and robust non-noble metal catalysts for water oxidation is a pivotal challenge for sustainable hydrogen production through electrocatalytic water splitting.Currently,such catalysts ...The development of low-cost,stable,and robust non-noble metal catalysts for water oxidation is a pivotal challenge for sustainable hydrogen production through electrocatalytic water splitting.Currently,such catalysts suffer from high overpotential and sluggish kinetics in oxygen evolution reactions(OERs).Herein,we report a“continuous”single-crystal honeycomb-like MXene/NiFeP_(x)–N-doped carbon(NC)heterostructure,in which ultrasmall NiFeP_(x)nanoparticles(NPs)encapsulated in the NC are tightly anchored on a layered MXene.Interestingly,this MXene/NiFeP_(x)–NC delivers outstanding OER catalytic performance,which stems from“continuous”single-crystal characteristics,abundant active sites derived from the ultrasmall NiFeP_(x)NPs,and the stable honeycomb-like heterostructure with an open structure.The experimental results are rationalized theoretically(by density functional theory(DFT)calculations),which suggests that it is the unique MXene/NiFeP_(x)–NC heterostructure that promotes the sluggish OER,thereby enabling superior durability and excellent activity with an ultralow overpotential of 240 mV at a current density of 10 mA×cm^(−2).展开更多
Transmucosal drug administration represents a potential strategy for enhancing treatment efficacy and reducing side effects by avoiding the first-pass effect into the systemic circulation and delivering therapeutics d...Transmucosal drug administration represents a potential strategy for enhancing treatment efficacy and reducing side effects by avoiding the first-pass effect into the systemic circulation and delivering therapeutics directly to the target disease site.However,many challenges still remain in its clinical application,including low drug availability and limited retention time in the mucosa.The burgeoning advancement of nanotechnologies offers great potential to overcome the above limitations,leveraging their distinct advantages of high drug-loading capacity and strong permeability.In this review,the latest developments of nanoparticles(NPs)in transmucosal drug delivery as well as their clinical applications are discussed.展开更多
Nano-magnetic ferrites with composition Mg_(1-x)Zn_(x)Fe_(2)O_(4)(x=0.3,0.4,0.5,0.6,and 0.7)have been prepared by coprecipitation method.X-ray diffraction(XRD)studies showed that the lattice parameter was found to inc...Nano-magnetic ferrites with composition Mg_(1-x)Zn_(x)Fe_(2)O_(4)(x=0.3,0.4,0.5,0.6,and 0.7)have been prepared by coprecipitation method.X-ray diffraction(XRD)studies showed that the lattice parameter was found to increase from 8.402 to 8.424A with Zn^(2+) ion content from 0.3 to 0.7.Fourier transform infrared(FTIR)spectra revealed two prominent peaks corresponding to tetrahedral and octahedral at around 560 and 430 cm^(-1) respectively that confirmed the spinel phase of the samples.Transmission electron microscopy(TEM)images showed that the particle size was noted to increase from 18 to 24 nm with an increase in Zn content from x=0.3 to 0.7.The magnetic properties were studied by vibrating sample magnetometer(VSM)and electron paramagnetic resonance(EPR)which ascertained the superparamagnetic behavior of the samples and contribution of superexchange interactions.The maximum magnetization was found to vary from 23.80 to 32.78 emu/g that increased till x=0.5 and decreased thereafter.Further,X-ray photoelectron spectroscopy(XPS)was employed to investigate the chemical composition and substantiate their oxidation states.展开更多
The Surface engineering of nanoparticles has contributed to the development of nanoscience and nanotechnology by designing of new material depends on their surface modifier with series of functional properties and app...The Surface engineering of nanoparticles has contributed to the development of nanoscience and nanotechnology by designing of new material depends on their surface modifier with series of functional properties and applications.The dispersed nanoparticles can change or modify the interfacial properties in liquid-liquid system in aqueous phase if their surface is modified by ionic surfactant.The interfacial energy in nanoparticles-brine system,the ions tends to modify the transport phenomena in pore channels and improve the recovery.The use of the suspension of the particles at nanoscales can offer some advantages of induced sedimentation stability by surface force easily counter balance the force of gravity.This happened due to their nanosize,nanostructure,high volume to surface ratio and strong rock fluid interaction.It also influences the emulsion stability and alters the surface characteristics of surfactant and polymer within the rock in porous medium.Some of the problems associated with conventional EOR processes have been solved by nanoscience applications due to their potential response to reduce the interfacial tension at low to ultra-low level,wettability reversal and improvement in rheology of formation fluids.The large specific surface area,high reactivity,toughness and other properties of Nanoparticles can immensely improve the oil mobility compare to conventional EOR.This paper updates the latest review,experimental evidences and re-interpretation of past research data and applications in respect of silica and titanium dioxide nanoparticles in different environment within surfactant(s),polymer(s),polymer-surfactant EOR processes.The nanotechnology therefore is an effective and alternate solution to brush up the traditional EOR approach with state of art technology which can revolutionize the total oil and gas industry and can contributes significantly to enhance the economics of oil field industry.展开更多
A thorough understanding of how proteins induce nanoparticle （NP） aggregation is crucial when designing in vitro and in vivo assays and interpreting experimental results. This knowledge is also crucial when developi...A thorough understanding of how proteins induce nanoparticle （NP） aggregation is crucial when designing in vitro and in vivo assays and interpreting experimental results. This knowledge is also crucial when developing nano-applications and formulation for drug delivery systems. In this study, we found that extraction of immunoglobulin G （IgG） from cow serum results in lower polystyrene NPs aggregation. Moreover, addition of isolated IgG or fibrinogen to fetal cow serum enhanced this aggregation, thus demonstrating that these factors are major drivers of NP aggregation in serum. Counter-intuitively, NP aggregation was inversely dependent on protein concentration; i.e., low protein concentrations induced large aggregates, whereas high protein concentrations induced small aggregates. Protein-induced NP aggregation and aggregate size were monitored by absorbance at 400 nm and dynamic light scattering, respectively. Here, we propose a mechanism behind the protein concentration dependent aggregation; this mechanism involves the effects of multiple protein interactions on the NP surface, surface area limitations, aggregation kinetics, and the influence of other serum proteins.展开更多
Ultraviolet(UV)radiation can cause degradation or aging of many polymers and shorten the working-life of their products.Thus,UV protective covers are required in various occasions.Textiles with the UV-shielding functi...Ultraviolet(UV)radiation can cause degradation or aging of many polymers and shorten the working-life of their products.Thus,UV protective covers are required in various occasions.Textiles with the UV-shielding function possess unique properties compared with those covers in board or film shapes.TiO_2 nanoparticles(NPs),which were reported to have superior UV blocking function,can be used to produce UV protective covers in combination with fabric.However,efficient and environmentally friendly immobilization of TiO_2 Nps onto the fabrics is challenging.Polydopamine(PDA),a biomimetic synthetic polymer,has attracted great attentions recently due to its superior affinity to various materials and facile application procedure.Hence,in this research,the surface of nylon fabrics was modified by PDA to immobilizeTiO_2 NPs.Themodificationconditionswere systematically optimized.The immobilization of the NPs was confirmed by Fourier transform infrared spectrometer(FTIR)and scanning electron microscope(SEM).The functionalized nylon fabrics were proved to exhibit improved UV protection properties even after washing.This work provides a new and versatile surface modification technique for textiles.展开更多
文摘Lubricants have played important roles in friction and wear reduction and increasing efficiency of mechanical systems.To optimize tribological performance,chemical reactions between a lubricant and a substrate must be designed strategically.Tribochemical reactions are chemical reactions enabled or accelerated by mechanical stimuli.Tribochemically activated lubricant additives play important roles in these reactions.In this review,current understanding in mechanisms of chemical reactions under shear has been discussed.Additives such as oil-soluble organics,ionic liquids(ILs),and nanoparticles(NPs)were analyzed in relation to the tribochemical reaction routes with elements in metallic substrates.The results indicated that phosphorus,sulfur,fluorine,and nitrogen are key elements for tribochemical reactions.The resulting tribofilms from zinc dithiophosphates(ZDDP)and molybdenum dithiocarbamate(MoDTC)have been widely reported,yet that from ILs and NPs need to investigate further.This review serves as a reference for researchers to design and optimize new lubricants.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China （Nos. 21573286, 21173269, and 21572688）, Ministry ofScience and Technology of China （Nos. 2011BAK15B05 and 2015AA034603）, Specialized Research Fund for the Doctoral Program of Higher Education （No. 20130007110003）, and Science Foundation of China University of Petroleum, Beijing （No. 2462015YQ0304）.
文摘Controlled integration of ultrafine metal nanoparticles （MNPs） and metal- organic frameworks （MOFs） has drawn much attention due to their unique physical and chemical properties. However, the development of a one-step strategy for preparing ultrafine MNPs within MOFs still remains a great challenge. Herein, a facile synthetic approach toward the abovementioned composites was developed. In contrast to the conventional approach, these hybrids were prepared by the direct mixing of metal and MOF precursors in the reaction solution assisted by microwave irradiation. Impressively, the Au/MOF-199 composite with uniformly distributed ultrafine Au nanoparticles could be fabricated in only two minutes, and the Au loading could be increased up to a level of 5.13%. The multifunctional Au/MOF-199 catalysts exhibited high turnover numbers （TONs） and turnover frequencies （TOFs） in the three-component coupling reaction of formaldehyde, phenylacetylene, and piperidine （AB-coupling）. Owing to the confinement effect of MOF-199, the 5.13%Au/MOF-199 catalyst could be recycled for five runs without serious loss of activity, with no obvious aggregation of Au NPs detected.
基金supported by the National Natural Science Foundation of China(No.22269010)the Training Program for Academic and Technical Leaders of Major Disciplines in Jiangxi Province(No.20212BCJ23020)+1 种基金the Science and Technology Project of Jiangxi Provincial Department of Education(No.GJJ211305)Jingdezhen Science and Technology Planning Project(No.20212GYZD009-04)。
文摘The development of low-cost,stable,and robust non-noble metal catalysts for water oxidation is a pivotal challenge for sustainable hydrogen production through electrocatalytic water splitting.Currently,such catalysts suffer from high overpotential and sluggish kinetics in oxygen evolution reactions(OERs).Herein,we report a“continuous”single-crystal honeycomb-like MXene/NiFeP_(x)–N-doped carbon(NC)heterostructure,in which ultrasmall NiFeP_(x)nanoparticles(NPs)encapsulated in the NC are tightly anchored on a layered MXene.Interestingly,this MXene/NiFeP_(x)–NC delivers outstanding OER catalytic performance,which stems from“continuous”single-crystal characteristics,abundant active sites derived from the ultrasmall NiFeP_(x)NPs,and the stable honeycomb-like heterostructure with an open structure.The experimental results are rationalized theoretically(by density functional theory(DFT)calculations),which suggests that it is the unique MXene/NiFeP_(x)–NC heterostructure that promotes the sluggish OER,thereby enabling superior durability and excellent activity with an ultralow overpotential of 240 mV at a current density of 10 mA×cm^(−2).
基金supported by the National Natural Science Foundation of China(No.82100911)the Zhejiang Provincial Natural Science Foundation(No.LQ18H070004)to X.Y.+4 种基金the Zhejiang Provincial Natural Science Foundation(No.LY19H070002)to Y.X.S.the National Natural Science Foundation of China(No.32271380)to J.C.Y.,the National Natural Science Foundation of China(No.81970714)the Joint Funds of the Zhejiang Provincial Natural Science Foundation of China under Grant No.LHDMZ23H070001Science and technology innovation leading talent project of Zhejiang ten thousand people plan(No.2021R52022)Zhejiang province health innovative talents project(No.2021-CXRC07-01)to X.H.W.
文摘Transmucosal drug administration represents a potential strategy for enhancing treatment efficacy and reducing side effects by avoiding the first-pass effect into the systemic circulation and delivering therapeutics directly to the target disease site.However,many challenges still remain in its clinical application,including low drug availability and limited retention time in the mucosa.The burgeoning advancement of nanotechnologies offers great potential to overcome the above limitations,leveraging their distinct advantages of high drug-loading capacity and strong permeability.In this review,the latest developments of nanoparticles(NPs)in transmucosal drug delivery as well as their clinical applications are discussed.
文摘Nano-magnetic ferrites with composition Mg_(1-x)Zn_(x)Fe_(2)O_(4)(x=0.3,0.4,0.5,0.6,and 0.7)have been prepared by coprecipitation method.X-ray diffraction(XRD)studies showed that the lattice parameter was found to increase from 8.402 to 8.424A with Zn^(2+) ion content from 0.3 to 0.7.Fourier transform infrared(FTIR)spectra revealed two prominent peaks corresponding to tetrahedral and octahedral at around 560 and 430 cm^(-1) respectively that confirmed the spinel phase of the samples.Transmission electron microscopy(TEM)images showed that the particle size was noted to increase from 18 to 24 nm with an increase in Zn content from x=0.3 to 0.7.The magnetic properties were studied by vibrating sample magnetometer(VSM)and electron paramagnetic resonance(EPR)which ascertained the superparamagnetic behavior of the samples and contribution of superexchange interactions.The maximum magnetization was found to vary from 23.80 to 32.78 emu/g that increased till x=0.5 and decreased thereafter.Further,X-ray photoelectron spectroscopy(XPS)was employed to investigate the chemical composition and substantiate their oxidation states.
文摘The Surface engineering of nanoparticles has contributed to the development of nanoscience and nanotechnology by designing of new material depends on their surface modifier with series of functional properties and applications.The dispersed nanoparticles can change or modify the interfacial properties in liquid-liquid system in aqueous phase if their surface is modified by ionic surfactant.The interfacial energy in nanoparticles-brine system,the ions tends to modify the transport phenomena in pore channels and improve the recovery.The use of the suspension of the particles at nanoscales can offer some advantages of induced sedimentation stability by surface force easily counter balance the force of gravity.This happened due to their nanosize,nanostructure,high volume to surface ratio and strong rock fluid interaction.It also influences the emulsion stability and alters the surface characteristics of surfactant and polymer within the rock in porous medium.Some of the problems associated with conventional EOR processes have been solved by nanoscience applications due to their potential response to reduce the interfacial tension at low to ultra-low level,wettability reversal and improvement in rheology of formation fluids.The large specific surface area,high reactivity,toughness and other properties of Nanoparticles can immensely improve the oil mobility compare to conventional EOR.This paper updates the latest review,experimental evidences and re-interpretation of past research data and applications in respect of silica and titanium dioxide nanoparticles in different environment within surfactant(s),polymer(s),polymer-surfactant EOR processes.The nanotechnology therefore is an effective and alternate solution to brush up the traditional EOR approach with state of art technology which can revolutionize the total oil and gas industry and can contributes significantly to enhance the economics of oil field industry.
文摘A thorough understanding of how proteins induce nanoparticle （NP） aggregation is crucial when designing in vitro and in vivo assays and interpreting experimental results. This knowledge is also crucial when developing nano-applications and formulation for drug delivery systems. In this study, we found that extraction of immunoglobulin G （IgG） from cow serum results in lower polystyrene NPs aggregation. Moreover, addition of isolated IgG or fibrinogen to fetal cow serum enhanced this aggregation, thus demonstrating that these factors are major drivers of NP aggregation in serum. Counter-intuitively, NP aggregation was inversely dependent on protein concentration; i.e., low protein concentrations induced large aggregates, whereas high protein concentrations induced small aggregates. Protein-induced NP aggregation and aggregate size were monitored by absorbance at 400 nm and dynamic light scattering, respectively. Here, we propose a mechanism behind the protein concentration dependent aggregation; this mechanism involves the effects of multiple protein interactions on the NP surface, surface area limitations, aggregation kinetics, and the influence of other serum proteins.
基金National Natural Science Foundation of China(No.51503031)Pujiang Project from Shanghai Science and Technology Committee,China(No.15PJ1400300)+1 种基金Scientific Research Foundation for the Returned Overseas Scholars from the Ministry of Education,China(No.15B10127)Fundamental Research Funds for the Central Universities,China(No.2232015D3-02)
文摘Ultraviolet(UV)radiation can cause degradation or aging of many polymers and shorten the working-life of their products.Thus,UV protective covers are required in various occasions.Textiles with the UV-shielding function possess unique properties compared with those covers in board or film shapes.TiO_2 nanoparticles(NPs),which were reported to have superior UV blocking function,can be used to produce UV protective covers in combination with fabric.However,efficient and environmentally friendly immobilization of TiO_2 Nps onto the fabrics is challenging.Polydopamine(PDA),a biomimetic synthetic polymer,has attracted great attentions recently due to its superior affinity to various materials and facile application procedure.Hence,in this research,the surface of nylon fabrics was modified by PDA to immobilizeTiO_2 NPs.Themodificationconditionswere systematically optimized.The immobilization of the NPs was confirmed by Fourier transform infrared spectrometer(FTIR)and scanning electron microscope(SEM).The functionalized nylon fabrics were proved to exhibit improved UV protection properties even after washing.This work provides a new and versatile surface modification technique for textiles.
