Photocatalytic activity of La-doped ZnO nanostructure materials synthesized by sonochemical method

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.

Laser Synthesis and Microfabrication of Micro/ Nanostructured Materials Toward Energy Conversion and Storage

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.

State-of-the-Art and Perspectives in the Field of Particulate Nanostructured Materials

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

CHARACTERIZATION OF NANOSTRUCTURED MATERIALS BY ANALYTICAL ELECTRON MICROSCOPY

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.

SnO_(2)nanostructured materials used as gas sensors for the detection of hazardous and flammable gases:A review

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.

Recent developments of the high strength and high ductility nanostructured materials

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.

Electrical Breakdown Characteristic of Nanostructured W-Cu Contacts Materials

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.

Biologically Enabled Syntheses of Nanostructured 3-D Sensor Materials:the Potential for 3-D Genetically Engineered Microdevices (3-D GEMs)

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.

Nanostructured hybrid materials for bone-tooth unit regeneration

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.

Some Factors Influencing the Dielectric Properties of Natural Rubber Composites Containing Different Carbon Nanostructures

Natural rubber based composites containing different carbon nanofillers (fullerenes, carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs)) at different concentrations have been prepared. Their dielectric properties (dielectric permittivity, dielectric loss) have been studied in the 1 - 12 GHz frequency range. Some factors (electromagnetic field frequency, fillers concentration, fillers intrinsic structure) influencing the dielectric behavior of the composites have been investigated. The dielectric properties of the developed natural rubber composites containing conductive fillers (fullerenes, CNTs, GNPs) indicate that these composites can be used as broadband microwave absorbing materials.

Preparation and visible-light photocatalytic property of nanostructured Fe-doped TiO_2 from titanium containing electric furnace molten slag

Nanostructured Fe-doped titanium dioxide was synthesized from titanium containing electric furnace molten slag （TCEFMS） by using an alkali fusion, followed by a hydrolyzation-acidolysis-cMcination route. The effects of Mkali/slag mass ratio, calcinating temperature, calcinating time, and water/slag mass ratio on the extraction efficiency and purity of products were systematically studied in this paper. It is indicated that the best extraction efficiency of nanostructured Fe- doped titanium dioxide is 99.35%, when the molten slag is calcinated at 700℃ for 1 h with the mass ratio of alkali/molten slag of 1.5：1. The influence of alkali/slag mass ratio on the photocatalytic activity of final products was evaluated by the photodegradation of methyl blue under visible light irradiation. A maximum photodegradation efficiency of 88.12% over 30 min was achieved under the optimum conditions.

Preparation and Arc Breakdown Behavior of Nanocrystalline W-Cu Electrical Contact Materials

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.

Effect of heat treatment on microstructures and mechanical properties of a bulk nanostructured Al-Zn-Mg-Cu alloy

A bulk nanostructured Al-10.0Zn-2.8Mg-1.8Cu alloy was synthesized by cryomilling first and then by spark plasma sintering （SPS）, and the effect of heat treatment on the microstructures and mechanical properties of this alloy were studied. Most MgZn2 particles with a coarse size lie on the grain boundaries of the SPS-processed sample. After solid solution and artificial aging, fine spherical-like MgZn2 particles precipitate uniformly in the grain interiors. No obvious grain growth is found after the heat treatment. A nanoindentation study indicates that no clear change is found in the Yong＇s modulus of the nanostructured alloy after the heat treatment. However, the hardness of the nanostructured alloy increases by about 33% after the heat treatment, which is attributed to the effect of precipitation-hardening.

Environmentally‐friendly carbon nanomaterials for photocatalytic hydrogen production

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.

Recent advances in nanomaterials for high-performance Li–S batteries

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.

Activator-assisted electroless deposition of copper nanostructured films

This paper showed simple and effective synthesis of copper nanoparticles within controlled diameter using direct electroless deposition on glass substrates, following the sensitization and activation steps. Electroless-deposited metals, such as Cu, Co, Ni, and Ag, and their alloys had many advantages in micro- and nanotechnologies. The structural, morphological, and optical properties of copper deposits were characterized using X-ray diffraction （XRD）, atomic force microscopy （AFM）, and UV-Vis spectroscopy. The structural data was further analyzed using the Rietveld refinement program. Structural studies reveal that the deposited copper prefers a （111） orientation. AFM studies suggest the deposited materials form compact, uniform, and nanocrystalline phases with a high tendency to self-organize. The data show that the particle size can be controlled by controlling the activator concentration. The absorption spectra of the as-deposited copper nanoparticles reveal that the plasmonic peak broadens and exhibits a blue shift with decreasing particle size.

Recent Advances and Perspective on Design and Synthesis of Electrode Materials for Electrochemical Sensing of Heavy Metals

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.

Effects of ausforming strain on bainite transformation in nanostructured bainite steel

The effects of ausforming strain on bainite transformation in high-carbon low-alloy nanobainite steel were investigated using a Gleeble 3500 thermomechanical simulator machine. The bainite transformation speed at 300°C was found to be accelerated by ausforming at 300, 600, and 700°C under applied strains ranging from 10% to 50% followed by isothermal transformation at 300°C. The ausformed bainite volume fraction varied with the ausforming strain because of the mechanical stabilization of the deformed austenite. Ausforming at low temperatures not only enhanced the bainite ferrite volume fraction but also refined the microstructure substantially. Although the amount of bainite ferrite might have been reduced with increasing strain, the microstructures were refined by ausforming. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

Practical fuel cells enabled by unprecedented oxygen reduction reaction on 3D nanostructured electrocatalysts

Oxygen reduction reaction(ORR)is of significance for energy conversion technologies such as fuel cells and metal-air batteries[1,2].Currently,the electrocatalysts still need to employ expensive precious metal platinum(Pt)as the main active component to overcome the sluggish kinetics of ORR[3,4].The exploration of low-cost.

Investigations of a nanostructured FeMnSi shape memory alloy produced via severe plastic deformation

Low-cost iron-based shape memory alloys（SMAs） show great potential for engineering applications. The developments of new processing techniques have recently enabled the production of nanocrystalline materials with improved properties. These developments have opened avenues for newer applications for SMAs. The influence of severe plastic deformation induced by the high-speed high-pressure torsion（HSHPT） process on the microstructural evolution of an Fe–Mn–Si–Cr alloy was investigated. Transmission electron microscopic analysis of the alloy revealed the existence of nanoscale grains with an abundance of stacking faults. The high density of dislocations characteristic of severe plastic deformation was not observed in this alloy. X-ray diffraction studies revealed the presence of ε-martensite with an HCP crystal structure and γ-phase with an FCC structure.