Gold nanoparticles were assembled on gold substrates with the self-assembled monolayer(SAM) of p-minothiophenol(PATP). AFM measurements disclose that gold nanoparticles are scattered over the surface of the substrate ...Gold nanoparticles were assembled on gold substrates with the self-assembled monolayer(SAM) of p-minothiophenol(PATP). AFM measurements disclose that gold nanoparticles are scattered over the surface of the substrate with a submonolayer coverage. The Raman signal of the coupling layer, the SAM of PATP, can be well observed. Potential-dependent measurements were performed to study the chemical enhancement in SERS of such a system. Based on the supposition that the direction of charge transfer is from gold nanoparticles to PATP, it is deduced that Herzberg-Teller contribution has ruled in the SERS of such a system.展开更多
Broadband near-infrared(NIR)luminescent materials have shown great promise in applications such as optical communication,biomedicine,and optoelectronic devices.However,the current research is focused on phos⁃phors and...Broadband near-infrared(NIR)luminescent materials have shown great promise in applications such as optical communication,biomedicine,and optoelectronic devices.However,the current research is focused on phos⁃phors and glasses,and it is important to develop broadband NIR luminescent nanomaterials.Here,we report an erbi⁃um-sensitized core-shell nanocrystal design for broadband NIR emission.Based on the structural design with suitable dopings of Tm^(3+)and Ho^(3+),the broadband NIR emission covering 1.5-2.1μm region is achieved under 980 nm and 808 nm excitations.Moreover,the emission intensity is further enhanced by introducing Yb^(3+)and Nd^(3+)into the sam⁃ple,respectively,and the energy transfer processes between them are systematically discussed.Our results present a novel approach for developing broadband NIR luminescent materials and devices.展开更多
A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with ...A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with a size of approximately 3.69 nm was evenly distributed on spongy‑like porous Pyr‑GDY.The catalyst exhibited a good electrocatalytic activity for N_(2)reduction in a nitrogen‑saturated electrolyte,with an ammonia yield of 32.1μg·h^(-1)·mg_(cat)^(-1)at-0.3 V(vs RHE),3.5 times higher than that of Au/C(Au NPs anchored on carbon black).In addition,Au/Pyr‑GDY showed a Faraday efficiency(FE)of 26.9%for eNRR,and a good catalysis durability for over 22 h.展开更多
Sm^(3+)-doped materials exhibit red and orange emissions in the visible light region,showing broad applica⁃tion prospects in both laser and display material fields.However,the inherent small emission and absorption cr...Sm^(3+)-doped materials exhibit red and orange emissions in the visible light region,showing broad applica⁃tion prospects in both laser and display material fields.However,the inherent small emission and absorption cross-sections of Sm^(3+)result in low luminous efficiency,posing challenges for achieving high-quality solid-state lighting.Here,the excellent white emission of Sm^(3+)doped lithium aluminum silicate(LAS)glass was realized by introducing the Ag aggregates through Ag ion exchange.Under 395 nm excitation,the Ag-doped samples exhibit significant fluo⁃rescence enhancement with color coordinates close to the equal energy white point E(0.33,0.33)and a color ren⁃dering index(CRI)of 81.8.The study reveals that the surface plasmon resonance(SPR)effect of Ag nanoparticles enhances the luminescence of Sm^(3+),while the energy transfer mechanism between Ag^(+)and Sm^(3+)also promotes fluores⁃cence enhancement.By adjusting the concentration of AgNO_(3) and the exchange time,a series of high-quality full-spectrum white light emissions were obtained,indicating that the Ag ion-exchanged Sm^(3+)-doped LAS glass has good application potential in the development of solid-state lighting devices.Moreover,variations in the excitation wave⁃length can effectively tune the emission color,further demonstrating the tunability and practicality of this material in optoelectronic applications.展开更多
The heat transfer between two corresponding plates,disks,and concentric pipes has many applications,including water cleansing and lubrication.Furthermore,TiO_(2)-water-based nanofluids are used widely because it is us...The heat transfer between two corresponding plates,disks,and concentric pipes has many applications,including water cleansing and lubrication.Furthermore,TiO_(2)-water-based nanofluids are used widely because it is useful for operating and controlling the temperature,especially in photovoltaic technology and solar panels.Motivated by these applications,the current study is based on the nanoparticle aggregation effect on magnetohydrodynamics(MHD)flow via rotating parallel plates with the chemical reaction.To achieve maximum heat transportation,the Bruggeman model is used to adapt the Maxwell model.Also,melting and thermal radiation effects are considered in the modeling to discuss heat transport.The Runge-Kutta-Fehlberg 4th−5th order method is used to attain numerical solutions.The main focus of this study is to see the thermodynamic behavior considering several aspects of nanoparticle aggregation.The heat transfer rate between the parallel plates is enhanced by improving the thermophoresis,radiation,and Brownian motion parameters.The rise in Schmidt number and chemical reaction rate parameter decreases the concentration distribution.This study will be helpful in enhancing the thermal efficiency of photovoltaic technology in solar plates,water purifying,thermal management of electronic devices,designing effective cooling systems,and other sustainable technologies.展开更多
Metal⁃organic framework(MOF)MIL⁃101 and surface plasmon polariton(SPP)supported gold nanoparti⁃cles(Au NPs)hybrid systems were developed as a highly sensitive and reproducible surface⁃enhanced Raman scat⁃tering(SERS)d...Metal⁃organic framework(MOF)MIL⁃101 and surface plasmon polariton(SPP)supported gold nanoparti⁃cles(Au NPs)hybrid systems were developed as a highly sensitive and reproducible surface⁃enhanced Raman scat⁃tering(SERS)detection platform,in which a green electrostatic self⁃assembly technology was adopted to construct the substrate.In an aqueous solution,the electronegativity of the particles can be used to prepare the composite sub⁃strate without any surface modifier.Due to the enrichment capacity of MIL⁃101 and the electromagnetic enhance⁃ment from Au NPs,the well⁃designed MIL⁃101/Au composites possessed ultrahigh sensitivity with the detection limit of Rhodamine 6G(R6G)as low as 10^(-10) mol·L^(-1).Meanwhile,the substrate exhibits high stability,excellent reproduc⁃ibility,and recyclability.Additionally,the novel substrate can be explored for direct capture,and sensitively detect pesticide residues such as thiram.展开更多
Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported ...Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported on factors governing tool life in machining superalloys,no study was found on the effect of nanoparticles stability on nanofluid performance and consequently resulted tool wear morphologies.In the present work,the nanoparticles were reinforced by means of improving the stability of the base fluid.To that accomplished,the surface active agent (surfactant) was added to the base cutting fluid as a reinforcing element.The effects of new lubricant on the tool wear morphology of A286 works parts were assessed.展开更多
In this paper,15Cr-ODS steels containing 0,1 wt%,2 wt%and 3 wt%Al element were fabricated by combining wet-milling and spark plasma sintering(SPS)methods.The microstructure and mechanical properties of ODS steel were ...In this paper,15Cr-ODS steels containing 0,1 wt%,2 wt%and 3 wt%Al element were fabricated by combining wet-milling and spark plasma sintering(SPS)methods.The microstructure and mechanical properties of ODS steel were investigated by XRD,SEM,TEM,EBSD and tensile tests.The results demonstrate that the Al addition significantly refines the particle precipitates in the Fe-Cr matrix,leading to the obvious refinement in grain size of matrix and the improvement of mechanical properties.The dispersion particles in ODS steels with Al addition are identified as Al2O3 and Y_(2)Ti_(2)O_(7)nanoparticles,which has a heterogeneous size distribution in the range of 5 nm to 300 nm.Increasing Al addition causes an obvious increase in tensile strength and a decline in elongation.The tensile strength and elongation of 15Cr-ODS steel containing 3 wt%Al are 775.3 MPa and 15.1%,respectively.The existence of Al element improves the corrosion resistance of materials.The ODS steel containing 2 wt%Al shows corrosion potential of 0.39 V and passivation current density of 2.61×10^(−3)A/cm^(2)(1.37 V).This work shows that Al-doped ODS steels prepared by wet-milling and SPS methods have a potential application in structural parts for nuclear system.展开更多
The solution chemical and optical characteristics of formation of amine-terminated polyamidoamine dendrimer G2.0（NH2-PAMAM G2.0）-Au nanocomposites in the aqueous solution of NH2-PAMAM G2.0 at various mole ratios of...The solution chemical and optical characteristics of formation of amine-terminated polyamidoamine dendrimer G2.0（NH2-PAMAM G2.0）-Au nanocomposites in the aqueous solution of NH2-PAMAM G2.0 at various mole ratios of Au（Ⅲ） to NH2-PAMAM G2.0 were studied by both UV-visible spectrometry and fluorospectrometry. The NH2-PAMAM G2.0-Au nanocomposites, with a type of structure in which one Au nanoparticle is surrounded by several NH2-PAMAM G2.0 dendrimers, emit strong bluish violet fluorescence, and are uniform, water soluble and biocompatible as well as very stable in frozen conditions. The size of gold nanoparticles in the nanocomposites is about 2.5 nm and decreases with the increase of NH2-PAMAM G2.0 concentration. The NH2-PAMAM G2.0 plays an important role in acting as host or micro-reactor for Au（Ⅲ） before Au（Ⅲ） reduction and acting as dispersant and stabilizer for gold nanoparticles after Au（Ⅲ） reduction. Preliminary experiments of cells staining to human embryonic lung fibroblast cell lines show that the NH2-PAMAM G2.0-Au nanocomposites can be used as optical imaging markers for bioanalyses and medical diagnoses.展开更多
In order to investigate the mechanism of nanoparticles enhancing the heat and mass transfer of the ammonia-water absorption process,several types of binary nanofluids were prepared by mixing Al2O3 nanoparticles with p...In order to investigate the mechanism of nanoparticles enhancing the heat and mass transfer of the ammonia-water absorption process,several types of binary nanofluids were prepared by mixing Al2O3 nanoparticles with polyacrylic acid(PAA),TiO2 with polyethylene glycol(PEG 1000),and TiN,SiC,hydroxyapatite(noodle-like) with PEG 10000 to ammonia-water solution,respectively.The thermal conductivities were measured by using a KD2 Pro thermal properties analyzer.The influences of surfactant and ammonia on the dispersion stabilities of the binary nanofluids were investigated by the light absorbency ratio index methods.The results show that the type,content and size of nanoparticles,the temperature as well as the dispersion stability are the key parameters that affect the thermal conductivity of nanofluids.For the given nanoparticle material and the base fluid,the thermal conductivity ratio of the nanofluid to the ammonia-water liquid increases as the nanoparticle content and the temperature are increased,and the diameter of nanoparticle is decreased.Furthermore,the thermal conductivity ratio increases significantly by improving the stabilities of nanofluids,which is achieved by adding surfactants or performing the proper ammonia content in the fluid.展开更多
Bioconvection plays an inevitable role in introducing sustainable and environment-friendly fuel cell technologies.Bio-mathematical modelling of such designs needs continuous refinements to achieve strong agreements in...Bioconvection plays an inevitable role in introducing sustainable and environment-friendly fuel cell technologies.Bio-mathematical modelling of such designs needs continuous refinements to achieve strong agreements in experimental and computational results.Actually,microorganisms transport a miscellaneous palette of ingredients in manufacturing industrial goods particularly in fertilizer industries.Heat transfer characteristics of molecular structure are measured by a physical phenomenon which is allied with the transpiration of heat within matter.Motivated by bioinspired fuel cells involved in near-surface flow phenomena,in the present article,we examine the transverse swimming of motile gyrotactic microorganisms numerically in a rheological Jeffery fluid near a stretching wall.The leading physical model is converted in a nonlinear system of ODEs through proper similarity alterations.A numerical technique called shooting method with R-K Fehlberg is applied via mathematical software and graphical presentations are obtained.The influence of all relative physical constraints on velocity,temperature,concentration,and volume fraction of gyrotactic microorganisms is expressed geometrically.It is found that heat and mass flux at the surface as well as density of motile microorganism’s declines for Brownian motion and thermophoresis parameter.Comparison in tabular form is made with existing literature to validate the results for limiting cases with convective boundary conditions.展开更多
文摘Gold nanoparticles were assembled on gold substrates with the self-assembled monolayer(SAM) of p-minothiophenol(PATP). AFM measurements disclose that gold nanoparticles are scattered over the surface of the substrate with a submonolayer coverage. The Raman signal of the coupling layer, the SAM of PATP, can be well observed. Potential-dependent measurements were performed to study the chemical enhancement in SERS of such a system. Based on the supposition that the direction of charge transfer is from gold nanoparticles to PATP, it is deduced that Herzberg-Teller contribution has ruled in the SERS of such a system.
文摘Broadband near-infrared(NIR)luminescent materials have shown great promise in applications such as optical communication,biomedicine,and optoelectronic devices.However,the current research is focused on phos⁃phors and glasses,and it is important to develop broadband NIR luminescent nanomaterials.Here,we report an erbi⁃um-sensitized core-shell nanocrystal design for broadband NIR emission.Based on the structural design with suitable dopings of Tm^(3+)and Ho^(3+),the broadband NIR emission covering 1.5-2.1μm region is achieved under 980 nm and 808 nm excitations.Moreover,the emission intensity is further enhanced by introducing Yb^(3+)and Nd^(3+)into the sam⁃ple,respectively,and the energy transfer processes between them are systematically discussed.Our results present a novel approach for developing broadband NIR luminescent materials and devices.
文摘A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with a size of approximately 3.69 nm was evenly distributed on spongy‑like porous Pyr‑GDY.The catalyst exhibited a good electrocatalytic activity for N_(2)reduction in a nitrogen‑saturated electrolyte,with an ammonia yield of 32.1μg·h^(-1)·mg_(cat)^(-1)at-0.3 V(vs RHE),3.5 times higher than that of Au/C(Au NPs anchored on carbon black).In addition,Au/Pyr‑GDY showed a Faraday efficiency(FE)of 26.9%for eNRR,and a good catalysis durability for over 22 h.
文摘Sm^(3+)-doped materials exhibit red and orange emissions in the visible light region,showing broad applica⁃tion prospects in both laser and display material fields.However,the inherent small emission and absorption cross-sections of Sm^(3+)result in low luminous efficiency,posing challenges for achieving high-quality solid-state lighting.Here,the excellent white emission of Sm^(3+)doped lithium aluminum silicate(LAS)glass was realized by introducing the Ag aggregates through Ag ion exchange.Under 395 nm excitation,the Ag-doped samples exhibit significant fluo⁃rescence enhancement with color coordinates close to the equal energy white point E(0.33,0.33)and a color ren⁃dering index(CRI)of 81.8.The study reveals that the surface plasmon resonance(SPR)effect of Ag nanoparticles enhances the luminescence of Sm^(3+),while the energy transfer mechanism between Ag^(+)and Sm^(3+)also promotes fluores⁃cence enhancement.By adjusting the concentration of AgNO_(3) and the exchange time,a series of high-quality full-spectrum white light emissions were obtained,indicating that the Ag ion-exchanged Sm^(3+)-doped LAS glass has good application potential in the development of solid-state lighting devices.Moreover,variations in the excitation wave⁃length can effectively tune the emission color,further demonstrating the tunability and practicality of this material in optoelectronic applications.
基金Large research project(RGP2/159/45)supported by the Deanship of Research and Graduate Studies at King Khalid University,Saudi Arabia。
文摘The heat transfer between two corresponding plates,disks,and concentric pipes has many applications,including water cleansing and lubrication.Furthermore,TiO_(2)-water-based nanofluids are used widely because it is useful for operating and controlling the temperature,especially in photovoltaic technology and solar panels.Motivated by these applications,the current study is based on the nanoparticle aggregation effect on magnetohydrodynamics(MHD)flow via rotating parallel plates with the chemical reaction.To achieve maximum heat transportation,the Bruggeman model is used to adapt the Maxwell model.Also,melting and thermal radiation effects are considered in the modeling to discuss heat transport.The Runge-Kutta-Fehlberg 4th−5th order method is used to attain numerical solutions.The main focus of this study is to see the thermodynamic behavior considering several aspects of nanoparticle aggregation.The heat transfer rate between the parallel plates is enhanced by improving the thermophoresis,radiation,and Brownian motion parameters.The rise in Schmidt number and chemical reaction rate parameter decreases the concentration distribution.This study will be helpful in enhancing the thermal efficiency of photovoltaic technology in solar plates,water purifying,thermal management of electronic devices,designing effective cooling systems,and other sustainable technologies.
文摘Metal⁃organic framework(MOF)MIL⁃101 and surface plasmon polariton(SPP)supported gold nanoparti⁃cles(Au NPs)hybrid systems were developed as a highly sensitive and reproducible surface⁃enhanced Raman scat⁃tering(SERS)detection platform,in which a green electrostatic self⁃assembly technology was adopted to construct the substrate.In an aqueous solution,the electronegativity of the particles can be used to prepare the composite sub⁃strate without any surface modifier.Due to the enrichment capacity of MIL⁃101 and the electromagnetic enhance⁃ment from Au NPs,the well⁃designed MIL⁃101/Au composites possessed ultrahigh sensitivity with the detection limit of Rhodamine 6G(R6G)as low as 10^(-10) mol·L^(-1).Meanwhile,the substrate exhibits high stability,excellent reproduc⁃ibility,and recyclability.Additionally,the novel substrate can be explored for direct capture,and sensitively detect pesticide residues such as thiram.
文摘Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported on factors governing tool life in machining superalloys,no study was found on the effect of nanoparticles stability on nanofluid performance and consequently resulted tool wear morphologies.In the present work,the nanoparticles were reinforced by means of improving the stability of the base fluid.To that accomplished,the surface active agent (surfactant) was added to the base cutting fluid as a reinforcing element.The effects of new lubricant on the tool wear morphology of A286 works parts were assessed.
基金Project(2020JJ2001)supported by Outstanding Youth Scientist Foundation of Hunan Province,ChinaProject(6142912200102)supported by Foundation for National Key Laboratory of Science and Technology on Highstrength Structural Materials,China。
文摘In this paper,15Cr-ODS steels containing 0,1 wt%,2 wt%and 3 wt%Al element were fabricated by combining wet-milling and spark plasma sintering(SPS)methods.The microstructure and mechanical properties of ODS steel were investigated by XRD,SEM,TEM,EBSD and tensile tests.The results demonstrate that the Al addition significantly refines the particle precipitates in the Fe-Cr matrix,leading to the obvious refinement in grain size of matrix and the improvement of mechanical properties.The dispersion particles in ODS steels with Al addition are identified as Al2O3 and Y_(2)Ti_(2)O_(7)nanoparticles,which has a heterogeneous size distribution in the range of 5 nm to 300 nm.Increasing Al addition causes an obvious increase in tensile strength and a decline in elongation.The tensile strength and elongation of 15Cr-ODS steel containing 3 wt%Al are 775.3 MPa and 15.1%,respectively.The existence of Al element improves the corrosion resistance of materials.The ODS steel containing 2 wt%Al shows corrosion potential of 0.39 V and passivation current density of 2.61×10^(−3)A/cm^(2)(1.37 V).This work shows that Al-doped ODS steels prepared by wet-milling and SPS methods have a potential application in structural parts for nuclear system.
文摘The solution chemical and optical characteristics of formation of amine-terminated polyamidoamine dendrimer G2.0（NH2-PAMAM G2.0）-Au nanocomposites in the aqueous solution of NH2-PAMAM G2.0 at various mole ratios of Au（Ⅲ） to NH2-PAMAM G2.0 were studied by both UV-visible spectrometry and fluorospectrometry. The NH2-PAMAM G2.0-Au nanocomposites, with a type of structure in which one Au nanoparticle is surrounded by several NH2-PAMAM G2.0 dendrimers, emit strong bluish violet fluorescence, and are uniform, water soluble and biocompatible as well as very stable in frozen conditions. The size of gold nanoparticles in the nanocomposites is about 2.5 nm and decreases with the increase of NH2-PAMAM G2.0 concentration. The NH2-PAMAM G2.0 plays an important role in acting as host or micro-reactor for Au（Ⅲ） before Au（Ⅲ） reduction and acting as dispersant and stabilizer for gold nanoparticles after Au（Ⅲ） reduction. Preliminary experiments of cells staining to human embryonic lung fibroblast cell lines show that the NH2-PAMAM G2.0-Au nanocomposites can be used as optical imaging markers for bioanalyses and medical diagnoses.
基金Projects(51176029,50876020) supported by the National Natural Science Foundation of ChinaProject(2011BAJ03B00) supported by the 12th Five-Year National Science and Technology Support Key Program of China Project(ybjj1124) supported by the Foundation of Graduate School of Southeast University,China
文摘In order to investigate the mechanism of nanoparticles enhancing the heat and mass transfer of the ammonia-water absorption process,several types of binary nanofluids were prepared by mixing Al2O3 nanoparticles with polyacrylic acid(PAA),TiO2 with polyethylene glycol(PEG 1000),and TiN,SiC,hydroxyapatite(noodle-like) with PEG 10000 to ammonia-water solution,respectively.The thermal conductivities were measured by using a KD2 Pro thermal properties analyzer.The influences of surfactant and ammonia on the dispersion stabilities of the binary nanofluids were investigated by the light absorbency ratio index methods.The results show that the type,content and size of nanoparticles,the temperature as well as the dispersion stability are the key parameters that affect the thermal conductivity of nanofluids.For the given nanoparticle material and the base fluid,the thermal conductivity ratio of the nanofluid to the ammonia-water liquid increases as the nanoparticle content and the temperature are increased,and the diameter of nanoparticle is decreased.Furthermore,the thermal conductivity ratio increases significantly by improving the stabilities of nanofluids,which is achieved by adding surfactants or performing the proper ammonia content in the fluid.
文摘Bioconvection plays an inevitable role in introducing sustainable and environment-friendly fuel cell technologies.Bio-mathematical modelling of such designs needs continuous refinements to achieve strong agreements in experimental and computational results.Actually,microorganisms transport a miscellaneous palette of ingredients in manufacturing industrial goods particularly in fertilizer industries.Heat transfer characteristics of molecular structure are measured by a physical phenomenon which is allied with the transpiration of heat within matter.Motivated by bioinspired fuel cells involved in near-surface flow phenomena,in the present article,we examine the transverse swimming of motile gyrotactic microorganisms numerically in a rheological Jeffery fluid near a stretching wall.The leading physical model is converted in a nonlinear system of ODEs through proper similarity alterations.A numerical technique called shooting method with R-K Fehlberg is applied via mathematical software and graphical presentations are obtained.The influence of all relative physical constraints on velocity,temperature,concentration,and volume fraction of gyrotactic microorganisms is expressed geometrically.It is found that heat and mass flux at the surface as well as density of motile microorganism’s declines for Brownian motion and thermophoresis parameter.Comparison in tabular form is made with existing literature to validate the results for limiting cases with convective boundary conditions.
