1 Results Molecular self-assembly of one-/two-dimensional(1D/2D)nanostructures has recently received great interest because the specific structures of crystals determine their unique physical and chemical properties.C...1 Results Molecular self-assembly of one-/two-dimensional(1D/2D)nanostructures has recently received great interest because the specific structures of crystals determine their unique physical and chemical properties.Coordination polymers contain two central components,connectors and linkers.Transition metal ions are often used as versatile connectors,with coordination numbers ranging from 2 to 7 dependant on the oxidation states of the metal ions.展开更多
Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics device...Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.展开更多
A sol-gel method and a modified chemical vapour deposition technique were used to produce nanostructured Ce0.6Sr0.4Fe0.8Co0.2O3-δ materials at temperatures as low as 400 ℃. Powders were characterized using Fourier t...A sol-gel method and a modified chemical vapour deposition technique were used to produce nanostructured Ce0.6Sr0.4Fe0.8Co0.2O3-δ materials at temperatures as low as 400 ℃. Powders were characterized using Fourier transform infrared spectroscopy （FTIR）, Raman spectroscopy, thermo gravimetric analysis, powder X-ray diffraction （XRD）, scanning electron microscopy （SEM） with energy dispersive X-ray spectroscopy, high resolution transmission electron microscopy （HRTEM）, and nitrogen sorption at 77 K. FTIR spectra showed that the sol-gel method resulted in residual carbon groups on the materials after calcination, while the Raman and XRD analysis confirmed that both synthesis methods resulted in cubic perovskite structure. However, the chemical va- pour deposition （CVD） method resulted in materials with a smaller crystallite size when compared to those prepared via the sol-gel route. The overall morphology of the powders was irregularly shaped aggregated particles as observed by SEM and HRTEM. In addition, HRTEM analysis showed that the materials were highly crystalline. Textural analysis revealed the powders had some mesoporosity, and the surface areas were 76.69 and 65.90 m2/g for materials synthesized using the CVD and sol-gel methods, respectively. The synthesized perovskite powders were used to fabricate button cells employing samarium doped ceria （SDC） as the electrolyte and NiO/SDC as the anode materials. As cathode materials, the maximum power density observed was 308.4 mW/cm2 at 500℃.展开更多
Nanostructured （NS） W-Cu composite powder was prepared by mechanical alloying （MA）, and nanostructured bulk of W-Cu contact material was fabricated by hot pressed sintering in an electrical vacuum furnace. The mic...Nanostructured （NS） W-Cu composite powder was prepared by mechanical alloying （MA）, and nanostructured bulk of W-Cu contact material was fabricated by hot pressed sintering in an electrical vacuum furnace. The microstructure, electric conductivity, hardness, breakdown voltage and arcing time of NS W-Cu alloys were measured and compared to conventional W-Cu alloys prepared by powder metallurgy. The results show that microstructural refinement and uniformity can improve the breakdown behavior, the electric arc stability and the arc extinction ability of nanostructured W-Cu contacts materials. Also, the nanostructured W-Cu contact material shows the characteristic of spreading electric arcs, which is of benefit to electric arc erosion.展开更多
Currently,the energy crisis is the crucial problem faced by the world,and photocatalytic hydrogen(H_(2))production is recognized with a chance to be a standout amongst those guaranteeing results to this issue.For a lo...Currently,the energy crisis is the crucial problem faced by the world,and photocatalytic hydrogen(H_(2))production is recognized with a chance to be a standout amongst those guaranteeing results to this issue.For a long time,photocatalytic H_(2) production has mainly relied on the noble metal cata‐lysts.However,the limitations of noble metals themselves,such as scarcity and high cost,have se‐verely restricted their large‐scale application.Therefore,it is urgent to seek a cheaper,more effi‐cient,and stable catalyst for photocatalytic H_(2) production.Fortunately,the emergence of carbon nanostructured materials(CNMs)has brought dawn.Its excellent structure and semiconductor performance can effectively participate in photocatalytic H_(2) production.CNMs have developed rap‐idly since they appeared in the field of photocatalytic water splitting.Therefore,it is necessary to summarize the latest progress of CNMs promptly for further development.This review introduced the CNMs,including carbon dots,fullerenes,carbon nanotubes,graphene,and graphdiyne,which is a powerful assistant in photocatalytic H_(2) production.CNMs can provide abundant adsorption and active sites,charge separation and transport channels,photocatalysts,co‐catalysts and photosensi‐tizers.Then,this review has introduced the strategy for enhancing CNMs in photocatalytic H_(2) pro‐duction based on recent research.Finally,the challenge faced by CNMs in photocatalytic H_(2) produc‐tion has prospected.展开更多
This article reviews nanotechnology as a practical solution for improving lithium-sulfur batteries. Lithiumsulfur batteries have been widely examined because sulfur has many advantageous properties such as a high crus...This article reviews nanotechnology as a practical solution for improving lithium-sulfur batteries. Lithiumsulfur batteries have been widely examined because sulfur has many advantageous properties such as a high crustal abundance, low environmental impact, low cost, high gravimetric(2600 W h kg-1) and volumetric(2800 W h L-1) energy densities, assuming complete conversion of sulfur to lithium sulfide(Li2S)upon lithiation. However, lithium-sulfur batteries have not yet reach commercialization due to demerits involving the formation of soluble lithium polysulfides(Li2Sn, n=3–8), low electrical conductivity, and low loading density of sulfur. These issues arise mainly due to the polysulfide shuttle phenomenon and the inherent insulating nature of sulfur. To overcome these issues, strategies have been pursued using nanotechnology applied to porous carbon nanocomposites, hollow one-dimensional carbon nanomaterials, graphene nanocomposites, and three-dimensional carbon nanostructured matrices. This paper aims to review various solutions pertaining to the role of nanotechnology in synthesizing nanoscale and nanostructured materials for advanced and high-performance lithium–sulfur batteries. Furthermore, we highlight perspective research directions for commercialization of lithium–sulfur batteries as a major power source for electric vehicles and large-scale electric energy storage.展开更多
A great attention has been paid to the research and development of nanostructured materials.The main preparation methods of ultrafine particles and nanostructured materials have been summarized. The applications of zo...A great attention has been paid to the research and development of nanostructured materials.The main preparation methods of ultrafine particles and nanostructured materials have been summarized. The applications of zone typical nanostructured materials have also been reviewed.The peculiar characteristics and properties. such as density, grain size, hardness, superplasticity,magnetic and catalytic properties have been discussed展开更多
The analytical electron microscopy has been used to characterize the morphology,structure and composition of the nanostructured material of Sn- Bi alloy prepared by a modified electrohydrodynamic technique. The electr...The analytical electron microscopy has been used to characterize the morphology,structure and composition of the nanostructured material of Sn- Bi alloy prepared by a modified electrohydrodynamic technique. The electron diffraction pattern and the corresponding contrast image for the discrete particles with a diameter smaller than 4 nm have been obtained.It is shown that the nanocrystalline Sn-Bi alloy particles comprise a single crystal of Bi-containing β-Sn solid solution or of Sn-containing Bi solid solution. A direct preparation procedure of the samples during the electrohydrodynamic rapid solidification process has been developed for electron microscopic observation.展开更多
The increase in release of toxic heavy metals into natural water attracts much attention due to its devastating effect on ecology and human health.The design and implementation of green electrode materials is pivotal ...The increase in release of toxic heavy metals into natural water attracts much attention due to its devastating effect on ecology and human health.The design and implementation of green electrode materials is pivotal for improving the electrochemical performance of in situ heavy metal monitoring.展开更多
SnO_(2)has been extensively used in the detection of various gases.As a gas sensing material,SnO_(2)has excellent physical-chemical properties,high reliability,and short adsorption-desorption time.The application of t...SnO_(2)has been extensively used in the detection of various gases.As a gas sensing material,SnO_(2)has excellent physical-chemical properties,high reliability,and short adsorption-desorption time.The application of the traditional SnO_(2)gas sensor is limited due to its higher work-temperature,low gas response,and poor selectivity.Nanomaterials can significantly impact gas-sensitive properties due to the quantum size,surface,and small size effects of nanomaterials.By applying nanotechnology to the preparation of SnO_(2),the SnO_(2)nanomaterial-based sensors could show better performance,which greatly expands the application of SnO_(2)gas sensors.In this review,the preparation method of the SnO_(2)nanostructure,the types of gas detected,and the improvements of SnO_(2)gas-sensing performances via elemental modification are introduced as well as the future development of SnO_(2)is discussed.展开更多
ZnO nanostructure materials doped with different La contents were synthesized by sonochemical method. The products were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）,transmission elect...ZnO nanostructure materials doped with different La contents were synthesized by sonochemical method. The products were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）,transmission electron microscopy（TEM）, Raman spectroscopy, and Fourier transform infrared spectroscopy（FTIR）. In this research, XRD patterns of pure ZnO and La-doped ZnO are specified as hexagonal wurtzite ZnO structure with no detection of La2O3 phase. SEM and TEM characterization revealed the flower shape of pure ZnO built-up from petals of hexagonal prisms with hexagonal pyramid tips. Upon doping with La, the flower-shaped ZnO is broken into individual 1D prism-like nanorods. Photocatalytic activities of the as-synthesized products were determined by measuring the degradation of methylene blue（MB） under ultraviolet–visible（UV） light irradiation.Among them, the 2.0 mol% La-doped ZnO shows better photocatalytic properties than any other products.展开更多
This talk will summarize the recent work related to a kind of new nanomaterials produced by the SMAT (surface mechanical attrition treatment).The concept of surface nanocrystallization of materials will be presented.I...This talk will summarize the recent work related to a kind of new nanomaterials produced by the SMAT (surface mechanical attrition treatment).The concept of surface nanocrystallization of materials will be presented.In terms of the grain refinement mechanism induced by plastic deformation,a novel surface mechanical attrition(SMA) technique was developed for synthesizing a nanostructured surface layer on metallic materials in order to upgrade the overall properties and performance.The grain refinement mechanism of the surface layer during the SMA treatment will be analyzed in terms of the nanostructure observations in several typical materials.Very high yield stress(5 times of the base material) on the surface layer of the material obtained by the SMAT has been observed.The effect of surface nanostructures on the mechanical behavior and on the failure mechanism of metallic material shows the possibility to develop a new strength gradient composite using co-rolling and nitriding.The role of residual stress induced during the treatment will be investigated and discussed.The developed materials are also porosity free materials which can be used as reference material for the local mechanical behavior investigation technique such as the nanoindentation.A general concept for obtaining high strength and high ductility nanostructured materials will be presented.The exceptional high strength and high ductility steels have developed.The simulation of the mechanisms for improving ductility of high strength nanostructured materials will be presented.The potential applications for the land transportation vehicles(car,bus,train) and wind energy have been investigated.Some examples of concept design for the integration of the advanced nanostructured steels will be presented.展开更多
Stable porphyrin-oxygenated carbon nanomaterial dispersions were prepared by blending porphyrin solutions with hydroxyl groups modified multi-walled carbon nanotubes(MWNTs-OH)and graphene oxide(GO)dispersions,respecti...Stable porphyrin-oxygenated carbon nanomaterial dispersions were prepared by blending porphyrin solutions with hydroxyl groups modified multi-walled carbon nanotubes(MWNTs-OH)and graphene oxide(GO)dispersions,respectively.Optical nonlinearity and optical limiting(OL)property of these blends are investigated in nanosecond regime.Results show that the OL performance of the blends can be tuned by changing the concentrations ratio of porphyrin and oxygenated carbon nanomaterials.The high concentration of oxygenated carbon nanomaterial leads to the poor OL performance.However,with the moderate concentration,the blends exhibit the low threshold value of OL and the enhanced OL performance at high fluence region.The superior OL performance can be attributed to complementary mechanisms and possible photoinduced electron or energy transfer between porphyrin moiety and oxygenated carbon nanomaterials.展开更多
Bulk nanocrystalline Fe3Al materials containing manganese of 10% were prepared by aluminothermic reaction.Hot pressing of those materials was performed at different temperatures and times.The microstructures of the al...Bulk nanocrystalline Fe3Al materials containing manganese of 10% were prepared by aluminothermic reaction.Hot pressing of those materials was performed at different temperatures and times.The microstructures of the alloy were investigated by optical microscope（OM） and electron probe microanalyzer（EPMA）.The grain sizes of the materials were analyzed by X-ray diffraction（XRD） and transmission electron microscope（TEM）.The results showed that the grain sizes of the materials increase after hot pressing.The grain sizes of the materials decrease with increasing the hot pressing times at the same temperature and the grain sizes of the materials increase with increasing hot pressing temperatures at identical times.The hardness and compressibility of the materials were also tested.The results showed that the hardness decreases with increasing hot pressing times at 800 ℃ and hardness increases with increasing the hot pressing temperatures.The variation of hardness with grain size of the nanocrystalline Fe3Al materials after hot pressing is contrary to the Hall-Petch relation.The materials are not broken during hot pressing and exhibit good plasticity and compressibility.展开更多
Developing high-capacity and low-cost cathode materials for metal-ion rechargeable batteries is the mainstream trend and is also the key to providing breakthroughs in making high-energy rechargeable batteries.Vanadium...Developing high-capacity and low-cost cathode materials for metal-ion rechargeable batteries is the mainstream trend and is also the key to providing breakthroughs in making high-energy rechargeable batteries.Vanadium has a variety of valence states and can form a variety of vanadate structures.As a typical positive electrode material,vanadate has abundant ion adsorption sites,a unique“pillar”framework,and a typical layered structure.Therefore,it has the advantages of high specific capacity and excellent rate performance,possessing the prospect of being a large-capacity energy storage material.In this review,we focus on applications of sodium vanadium oxides(NVO)in electrical energy storage(EES)devices and summarize sodium vanadate materials from three aspects,including crystal structure,electrochemical performance,and energy storage mechanism.The recent progress of NVO-based highperformance energy storage materials along with nanostructured design strategies was provided and discussed as well.This review is intended to serve as general guidance for researchers to develop desirable sodium vanadate materials.展开更多
Nanostructured （ NS ）W-Cu composite powder was prepared by mechanical alloying （ MA ）, and nanostructared bulk of W-Cu contact material was fabricated by hot press sintering in an electrical vacuum furnace. The rn...Nanostructured （ NS ）W-Cu composite powder was prepared by mechanical alloying （ MA ）, and nanostructared bulk of W-Cu contact material was fabricated by hot press sintering in an electrical vacuum furnace. The rnicrostructure, electric conductivity, hardness and break down voltage of NS W- Cu alloys were measured and compared to those of conventional W-Cu alloys prepared by powder metallurg＇y. The experimental results show that microstructural refinement and uniformity can improve the breakdown behavior and the electric arc stability of nanostructared W- Cu contacts materials. Also, the wanostructured W- Cu contact material shows the characteristic of spreading electric arcs, which is of benefit to electric arc erosion.展开更多
Three-dimensional (3-D)self-assembly of nanos- tructures and nanodevices on a large scale remains a grand quest for mankind.Freestanding nanostructured assemblies with controlled 3-D shapes can exhibit attractive prop...Three-dimensional (3-D)self-assembly of nanos- tructures and nanodevices on a large scale remains a grand quest for mankind.Freestanding nanostructured assemblies with controlled 3-D shapes can exhibit attractive properties for sensor and other applications. Protocols for 3-D self-assembly that can be scaled up for mass production on a large up to tonnage)scale, while preserving morphological features on a small (down to nanometer)scale,are needed to allow for widespread use of 3-D nanostructures in advanced devices.However,these often conflicting requirements of scalability and precision pose a difficult challenge for synthetic (man-made)processing routes.展开更多
As a part of regenerative medicine, biomaterials are largely used in this field of nanotechnology and tissue engineering research. We have recently developed a new scaffold using electrospun nanofibers of Poly (ε-cap...As a part of regenerative medicine, biomaterials are largely used in this field of nanotechnology and tissue engineering research. We have recently developed a new scaffold using electrospun nanofibers of Poly (ε-caprolactone), PCL which is able to mimic the collagen extracellular matrix of cells. The aim of this study was to engineer a biological and implantable structure leading the regeneration of the tooth-bone unit. For this aim, we have cultured mouse osteoblasts embedded in a collagen gel on the nanofibrous membrane and coupled this structure with an embryonic dental germ before implantation. To follow bone and tooth regeneration, we have performed RT-PCR, histology and immunofluorescence analysis. We showed here that this leaving implantable structure represents an accurate strategy for bone-tooth unit regeneration. We report here the first demonstration of bone-tooth unit regeneration by using a strategy based on a synthetic nanostructured membrane. This electrospun membrane is manufactured by using an FDA approved polymer, PCL and functionalized with osteoblasts before incorporation of the tooth germs at ED14 (the first lower molars) to generate bone-tooth unit in vivo after implantation in mice. Our technology represents an excellent platform on which other sophisticated products could be based.展开更多
1.Introduction The synthesis of bulk nanostructured multiphase(NM)mate-rials with extreme properties such as high hardness and strength is one of the most interesting research topics in materials science and engineeri...1.Introduction The synthesis of bulk nanostructured multiphase(NM)mate-rials with extreme properties such as high hardness and strength is one of the most interesting research topics in materials science and engineering[1].At present,NM alloys can be produced by several synthesis methods,including sintering of nanocomposites[2,3],physical or chemical vapour deposition(PVD or CVD)[4],crystallization of metallic glasses[5],and severe plastic deforma-tion(SPD)[6-8].However,industry applications of bulk NM alloys produced by these methods are significantly restricted by their ge-ometrical and size limitations.Thus,the fabrication of large-scale NM alloys remains challenging.展开更多
The microstructure and magnetic properties of Fe_(40)Co_(40)Zr_(9)B_(10)Ge_(1)(Mo-free)and Fe_(40)Co_(40)Zr_(5)Mo_(4)B_(10)Ge_(1)(Mocontaining)nanocrystalline alloys,prepared using an amorphous crystallization method,...The microstructure and magnetic properties of Fe_(40)Co_(40)Zr_(9)B_(10)Ge_(1)(Mo-free)and Fe_(40)Co_(40)Zr_(5)Mo_(4)B_(10)Ge_(1)(Mocontaining)nanocrystalline alloys,prepared using an amorphous crystallization method,were investigated.Mo addition affects the crystallization of the Fe_(40)Co_(40)Zr_(9)B_(10)Ge_(1) amorphous alloy and decreases the grain size of theα-Fe(Co)phase below 650℃.For the Mo-free alloy annealed at 600℃ and the Mo-containing alloy annealed at 575℃,with a singleα-Fe(Co)crystallization phase and approximately similar crystallization volume fractions,the Mo-containing alloy showed smaller,more regularly shaped grains and a significantly narrower grain-size distribution than the Mo-free alloy.The Fe and Co contents in the nanograins of the two alloys also differed.For the Mo-free alloy,a higher concentration of Co distributed in the residual amorphous matrix.For the Mo-containing alloy,a higher concentration Co dissolved in the nanograins.The specific saturation magnetization and coercivity of the Mo-free alloy were 1.05-and 1.59-times higher than those of the Mo-containing alloy,respectively.展开更多
文摘1 Results Molecular self-assembly of one-/two-dimensional(1D/2D)nanostructures has recently received great interest because the specific structures of crystals determine their unique physical and chemical properties.Coordination polymers contain two central components,connectors and linkers.Transition metal ions are often used as versatile connectors,with coordination numbers ranging from 2 to 7 dependant on the oxidation states of the metal ions.
基金This work was supported by Taishan Scholars Project Special Funds(tsqn201812083)Natural Science Foundation of Shandong Province(ZR2019YQ20,2019JMRH0410,ZR2019BB001)the National Natural Science Foundation of China(51972147,51902132,52022037).
文摘Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.
基金Project supported by Eskom-Tertiary Education Support Programthe National Research Foundation of South Africa(Thuthuka Program,76318)
文摘A sol-gel method and a modified chemical vapour deposition technique were used to produce nanostructured Ce0.6Sr0.4Fe0.8Co0.2O3-δ materials at temperatures as low as 400 ℃. Powders were characterized using Fourier transform infrared spectroscopy （FTIR）, Raman spectroscopy, thermo gravimetric analysis, powder X-ray diffraction （XRD）, scanning electron microscopy （SEM） with energy dispersive X-ray spectroscopy, high resolution transmission electron microscopy （HRTEM）, and nitrogen sorption at 77 K. FTIR spectra showed that the sol-gel method resulted in residual carbon groups on the materials after calcination, while the Raman and XRD analysis confirmed that both synthesis methods resulted in cubic perovskite structure. However, the chemical va- pour deposition （CVD） method resulted in materials with a smaller crystallite size when compared to those prepared via the sol-gel route. The overall morphology of the powders was irregularly shaped aggregated particles as observed by SEM and HRTEM. In addition, HRTEM analysis showed that the materials were highly crystalline. Textural analysis revealed the powders had some mesoporosity, and the surface areas were 76.69 and 65.90 m2/g for materials synthesized using the CVD and sol-gel methods, respectively. The synthesized perovskite powders were used to fabricate button cells employing samarium doped ceria （SDC） as the electrolyte and NiO/SDC as the anode materials. As cathode materials, the maximum power density observed was 308.4 mW/cm2 at 500℃.
基金supported by the National Natural Science Fundation of China under grant No.50071043the Natural Science Fundation of Shaanxi province under grant No.2004E105.
文摘Nanostructured （NS） W-Cu composite powder was prepared by mechanical alloying （MA）, and nanostructured bulk of W-Cu contact material was fabricated by hot pressed sintering in an electrical vacuum furnace. The microstructure, electric conductivity, hardness, breakdown voltage and arcing time of NS W-Cu alloys were measured and compared to conventional W-Cu alloys prepared by powder metallurgy. The results show that microstructural refinement and uniformity can improve the breakdown behavior, the electric arc stability and the arc extinction ability of nanostructured W-Cu contacts materials. Also, the nanostructured W-Cu contact material shows the characteristic of spreading electric arcs, which is of benefit to electric arc erosion.
文摘Currently,the energy crisis is the crucial problem faced by the world,and photocatalytic hydrogen(H_(2))production is recognized with a chance to be a standout amongst those guaranteeing results to this issue.For a long time,photocatalytic H_(2) production has mainly relied on the noble metal cata‐lysts.However,the limitations of noble metals themselves,such as scarcity and high cost,have se‐verely restricted their large‐scale application.Therefore,it is urgent to seek a cheaper,more effi‐cient,and stable catalyst for photocatalytic H_(2) production.Fortunately,the emergence of carbon nanostructured materials(CNMs)has brought dawn.Its excellent structure and semiconductor performance can effectively participate in photocatalytic H_(2) production.CNMs have developed rap‐idly since they appeared in the field of photocatalytic water splitting.Therefore,it is necessary to summarize the latest progress of CNMs promptly for further development.This review introduced the CNMs,including carbon dots,fullerenes,carbon nanotubes,graphene,and graphdiyne,which is a powerful assistant in photocatalytic H_(2) production.CNMs can provide abundant adsorption and active sites,charge separation and transport channels,photocatalysts,co‐catalysts and photosensi‐tizers.Then,this review has introduced the strategy for enhancing CNMs in photocatalytic H_(2) pro‐duction based on recent research.Finally,the challenge faced by CNMs in photocatalytic H_(2) produc‐tion has prospected.
文摘This article reviews nanotechnology as a practical solution for improving lithium-sulfur batteries. Lithiumsulfur batteries have been widely examined because sulfur has many advantageous properties such as a high crustal abundance, low environmental impact, low cost, high gravimetric(2600 W h kg-1) and volumetric(2800 W h L-1) energy densities, assuming complete conversion of sulfur to lithium sulfide(Li2S)upon lithiation. However, lithium-sulfur batteries have not yet reach commercialization due to demerits involving the formation of soluble lithium polysulfides(Li2Sn, n=3–8), low electrical conductivity, and low loading density of sulfur. These issues arise mainly due to the polysulfide shuttle phenomenon and the inherent insulating nature of sulfur. To overcome these issues, strategies have been pursued using nanotechnology applied to porous carbon nanocomposites, hollow one-dimensional carbon nanomaterials, graphene nanocomposites, and three-dimensional carbon nanostructured matrices. This paper aims to review various solutions pertaining to the role of nanotechnology in synthesizing nanoscale and nanostructured materials for advanced and high-performance lithium–sulfur batteries. Furthermore, we highlight perspective research directions for commercialization of lithium–sulfur batteries as a major power source for electric vehicles and large-scale electric energy storage.
文摘A great attention has been paid to the research and development of nanostructured materials.The main preparation methods of ultrafine particles and nanostructured materials have been summarized. The applications of zone typical nanostructured materials have also been reviewed.The peculiar characteristics and properties. such as density, grain size, hardness, superplasticity,magnetic and catalytic properties have been discussed
文摘The analytical electron microscopy has been used to characterize the morphology,structure and composition of the nanostructured material of Sn- Bi alloy prepared by a modified electrohydrodynamic technique. The electron diffraction pattern and the corresponding contrast image for the discrete particles with a diameter smaller than 4 nm have been obtained.It is shown that the nanocrystalline Sn-Bi alloy particles comprise a single crystal of Bi-containing β-Sn solid solution or of Sn-containing Bi solid solution. A direct preparation procedure of the samples during the electrohydrodynamic rapid solidification process has been developed for electron microscopic observation.
基金The authors would like acknowledge the financial supports from National Pro-gram on Key Basic Research of China(973 Program,2015CB258400)the National Thousand Young Talents Program,Natural Science Foundation of China(51508213,51608217,and 21607046)+1 种基金Innovative and Interdisciplinary Team at HUST(0118261077)the Fundamental Research Funds for Central Universi-ties(2017KFYXJJ217).
文摘The increase in release of toxic heavy metals into natural water attracts much attention due to its devastating effect on ecology and human health.The design and implementation of green electrode materials is pivotal for improving the electrochemical performance of in situ heavy metal monitoring.
基金supported by National Natural Science Foundation of China(No.61761047 and 41876055)the Department of Science and Technology of Yunnan Province via the Key Project for the Science and Technology(Grant No.2017FA025)Program for Innovative Research Team(in Science and Technology)in University of Yunnan Province。
文摘SnO_(2)has been extensively used in the detection of various gases.As a gas sensing material,SnO_(2)has excellent physical-chemical properties,high reliability,and short adsorption-desorption time.The application of the traditional SnO_(2)gas sensor is limited due to its higher work-temperature,low gas response,and poor selectivity.Nanomaterials can significantly impact gas-sensitive properties due to the quantum size,surface,and small size effects of nanomaterials.By applying nanotechnology to the preparation of SnO_(2),the SnO_(2)nanomaterial-based sensors could show better performance,which greatly expands the application of SnO_(2)gas sensors.In this review,the preparation method of the SnO_(2)nanostructure,the types of gas detected,and the improvements of SnO_(2)gas-sensing performances via elemental modification are introduced as well as the future development of SnO_(2)is discussed.
基金financially supported by the National Research University Project for Chiang Mai University (CMU) from the Thailand’s Office of the Higher Education Commission, Thailand
文摘ZnO nanostructure materials doped with different La contents were synthesized by sonochemical method. The products were characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM）,transmission electron microscopy（TEM）, Raman spectroscopy, and Fourier transform infrared spectroscopy（FTIR）. In this research, XRD patterns of pure ZnO and La-doped ZnO are specified as hexagonal wurtzite ZnO structure with no detection of La2O3 phase. SEM and TEM characterization revealed the flower shape of pure ZnO built-up from petals of hexagonal prisms with hexagonal pyramid tips. Upon doping with La, the flower-shaped ZnO is broken into individual 1D prism-like nanorods. Photocatalytic activities of the as-synthesized products were determined by measuring the degradation of methylene blue（MB） under ultraviolet–visible（UV） light irradiation.Among them, the 2.0 mol% La-doped ZnO shows better photocatalytic properties than any other products.
文摘This talk will summarize the recent work related to a kind of new nanomaterials produced by the SMAT (surface mechanical attrition treatment).The concept of surface nanocrystallization of materials will be presented.In terms of the grain refinement mechanism induced by plastic deformation,a novel surface mechanical attrition(SMA) technique was developed for synthesizing a nanostructured surface layer on metallic materials in order to upgrade the overall properties and performance.The grain refinement mechanism of the surface layer during the SMA treatment will be analyzed in terms of the nanostructure observations in several typical materials.Very high yield stress(5 times of the base material) on the surface layer of the material obtained by the SMAT has been observed.The effect of surface nanostructures on the mechanical behavior and on the failure mechanism of metallic material shows the possibility to develop a new strength gradient composite using co-rolling and nitriding.The role of residual stress induced during the treatment will be investigated and discussed.The developed materials are also porosity free materials which can be used as reference material for the local mechanical behavior investigation technique such as the nanoindentation.A general concept for obtaining high strength and high ductility nanostructured materials will be presented.The exceptional high strength and high ductility steels have developed.The simulation of the mechanisms for improving ductility of high strength nanostructured materials will be presented.The potential applications for the land transportation vehicles(car,bus,train) and wind energy have been investigated.Some examples of concept design for the integration of the advanced nanostructured steels will be presented.
基金supported by the National Natural Science Foundation of China(No.61174010)the Shanxi International Cooperation Project(No.2012081043)+1 种基金the Shanxi Scholarship Council(No.2013-038)the Scientific Research Starting Foundation from Taiyuan University of Technology(No.tyut-rc201162a)
文摘Stable porphyrin-oxygenated carbon nanomaterial dispersions were prepared by blending porphyrin solutions with hydroxyl groups modified multi-walled carbon nanotubes(MWNTs-OH)and graphene oxide(GO)dispersions,respectively.Optical nonlinearity and optical limiting(OL)property of these blends are investigated in nanosecond regime.Results show that the OL performance of the blends can be tuned by changing the concentrations ratio of porphyrin and oxygenated carbon nanomaterials.The high concentration of oxygenated carbon nanomaterial leads to the poor OL performance.However,with the moderate concentration,the blends exhibit the low threshold value of OL and the enhanced OL performance at high fluence region.The superior OL performance can be attributed to complementary mechanisms and possible photoinduced electron or energy transfer between porphyrin moiety and oxygenated carbon nanomaterials.
基金Item Sponsored by National Natural Science Foundation of China(50674051)
文摘Bulk nanocrystalline Fe3Al materials containing manganese of 10% were prepared by aluminothermic reaction.Hot pressing of those materials was performed at different temperatures and times.The microstructures of the alloy were investigated by optical microscope（OM） and electron probe microanalyzer（EPMA）.The grain sizes of the materials were analyzed by X-ray diffraction（XRD） and transmission electron microscope（TEM）.The results showed that the grain sizes of the materials increase after hot pressing.The grain sizes of the materials decrease with increasing the hot pressing times at the same temperature and the grain sizes of the materials increase with increasing hot pressing temperatures at identical times.The hardness and compressibility of the materials were also tested.The results showed that the hardness decreases with increasing hot pressing times at 800 ℃ and hardness increases with increasing the hot pressing temperatures.The variation of hardness with grain size of the nanocrystalline Fe3Al materials after hot pressing is contrary to the Hall-Petch relation.The materials are not broken during hot pressing and exhibit good plasticity and compressibility.
基金the National Natural Science Foundation of China(Nos.51902296,22004112)the National Key R&D Program of China(No.2017YFA0208000)the Zhejiang Provincial Natural Science Foundation of China(No.LD21B050001)。
文摘Developing high-capacity and low-cost cathode materials for metal-ion rechargeable batteries is the mainstream trend and is also the key to providing breakthroughs in making high-energy rechargeable batteries.Vanadium has a variety of valence states and can form a variety of vanadate structures.As a typical positive electrode material,vanadate has abundant ion adsorption sites,a unique“pillar”framework,and a typical layered structure.Therefore,it has the advantages of high specific capacity and excellent rate performance,possessing the prospect of being a large-capacity energy storage material.In this review,we focus on applications of sodium vanadium oxides(NVO)in electrical energy storage(EES)devices and summarize sodium vanadate materials from three aspects,including crystal structure,electrochemical performance,and energy storage mechanism.The recent progress of NVO-based highperformance energy storage materials along with nanostructured design strategies was provided and discussed as well.This review is intended to serve as general guidance for researchers to develop desirable sodium vanadate materials.
基金Funded by the National Natural Science Foundation of China(No.50071043)
文摘Nanostructured （ NS ）W-Cu composite powder was prepared by mechanical alloying （ MA ）, and nanostructared bulk of W-Cu contact material was fabricated by hot press sintering in an electrical vacuum furnace. The rnicrostructure, electric conductivity, hardness and break down voltage of NS W- Cu alloys were measured and compared to those of conventional W-Cu alloys prepared by powder metallurg＇y. The experimental results show that microstructural refinement and uniformity can improve the breakdown behavior and the electric arc stability of nanostructared W- Cu contacts materials. Also, the wanostructured W- Cu contact material shows the characteristic of spreading electric arcs, which is of benefit to electric arc erosion.
文摘Three-dimensional (3-D)self-assembly of nanos- tructures and nanodevices on a large scale remains a grand quest for mankind.Freestanding nanostructured assemblies with controlled 3-D shapes can exhibit attractive properties for sensor and other applications. Protocols for 3-D self-assembly that can be scaled up for mass production on a large up to tonnage)scale, while preserving morphological features on a small (down to nanometer)scale,are needed to allow for widespread use of 3-D nanostructures in advanced devices.However,these often conflicting requirements of scalability and precision pose a difficult challenge for synthetic (man-made)processing routes.
文摘As a part of regenerative medicine, biomaterials are largely used in this field of nanotechnology and tissue engineering research. We have recently developed a new scaffold using electrospun nanofibers of Poly (ε-caprolactone), PCL which is able to mimic the collagen extracellular matrix of cells. The aim of this study was to engineer a biological and implantable structure leading the regeneration of the tooth-bone unit. For this aim, we have cultured mouse osteoblasts embedded in a collagen gel on the nanofibrous membrane and coupled this structure with an embryonic dental germ before implantation. To follow bone and tooth regeneration, we have performed RT-PCR, histology and immunofluorescence analysis. We showed here that this leaving implantable structure represents an accurate strategy for bone-tooth unit regeneration. We report here the first demonstration of bone-tooth unit regeneration by using a strategy based on a synthetic nanostructured membrane. This electrospun membrane is manufactured by using an FDA approved polymer, PCL and functionalized with osteoblasts before incorporation of the tooth germs at ED14 (the first lower molars) to generate bone-tooth unit in vivo after implantation in mice. Our technology represents an excellent platform on which other sophisticated products could be based.
基金funding from the Australian Research Council(ARC Discovery Project,Nos.DP200101408 and DP230100183).
文摘1.Introduction The synthesis of bulk nanostructured multiphase(NM)mate-rials with extreme properties such as high hardness and strength is one of the most interesting research topics in materials science and engineering[1].At present,NM alloys can be produced by several synthesis methods,including sintering of nanocomposites[2,3],physical or chemical vapour deposition(PVD or CVD)[4],crystallization of metallic glasses[5],and severe plastic deforma-tion(SPD)[6-8].However,industry applications of bulk NM alloys produced by these methods are significantly restricted by their ge-ometrical and size limitations.Thus,the fabrication of large-scale NM alloys remains challenging.
基金Project supported by the Natural Science Foundation of Jilin Province,China(Grant No.YDZJ202201ZYTS319)the Fund from Sinoma Institute of Materials Research(Guangzhou)Co.,Ltd.(SIMR)for assisting with the TEM characterization。
文摘The microstructure and magnetic properties of Fe_(40)Co_(40)Zr_(9)B_(10)Ge_(1)(Mo-free)and Fe_(40)Co_(40)Zr_(5)Mo_(4)B_(10)Ge_(1)(Mocontaining)nanocrystalline alloys,prepared using an amorphous crystallization method,were investigated.Mo addition affects the crystallization of the Fe_(40)Co_(40)Zr_(9)B_(10)Ge_(1) amorphous alloy and decreases the grain size of theα-Fe(Co)phase below 650℃.For the Mo-free alloy annealed at 600℃ and the Mo-containing alloy annealed at 575℃,with a singleα-Fe(Co)crystallization phase and approximately similar crystallization volume fractions,the Mo-containing alloy showed smaller,more regularly shaped grains and a significantly narrower grain-size distribution than the Mo-free alloy.The Fe and Co contents in the nanograins of the two alloys also differed.For the Mo-free alloy,a higher concentration of Co distributed in the residual amorphous matrix.For the Mo-containing alloy,a higher concentration Co dissolved in the nanograins.The specific saturation magnetization and coercivity of the Mo-free alloy were 1.05-and 1.59-times higher than those of the Mo-containing alloy,respectively.
