Fabrication of nanostructured metal nitrides with tailored composition and morphology
材料科学与工程专业英语13-unit 19-20 nanostructured materialsppt课件
• the changes of the chemical properties: increase of the surface to volume ratio
B
4.The colloidal mask is removed.
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3. The spheres size is reduced and a material B is depo1s3ited.
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14
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11
top-down and bottom-up approaches
• Bottoom-up techniques
Bulk materials
– Sol-gel 溶胶-凝胶
– Precipitation 沉淀
– Flame pyrolysis 火焰分解
– Electrodeposition 电沉积
• Ferromagnietic materials:铁磁性材料 • Thermal motion:热运动 • Permanent magnetic:永磁性的 • Paramagnet:顺磁体 • Superparamagnetism: 超顺磁性 • Giant magnetoresistive effect:巨磁阻效应
材料科学与工程专业英语
Special English for Materials Science and Engineering
Part 4 nanostructured materials
Unit19 Nanotechnology and nanostructured materials Unit 20 creation of nanostructured materials
纳米材料与微型机器外文文献翻译、中英文翻译
外文资料Nanotechnology and Micro-machine原文(一):NanomaterialNanomaterials and nanotechnology have become a magic word in modern society.Nanomaterials represent today’s cutting edge in the development of novel advanced materials which promise tailor-made functionality and unheard applications in all key technologies. So nanomaterials are considered as a great potential in the 21th century because of their special properties in many fields such as optics, electronics, magnetics, mechanics, and chemistry. These unique properties are attractive for various high performance applications. Examples include wear resistant surfaces, low temperature sinterable high-strength ceramics, and magnetic nanocomposites. Nanostructures materials present great promises and opportunities for a new generation of materials with improved and marvelous properties.It is appropriate to begin with a brief introduction to the history of the subject. Nanomaterials are found in both biological systems and man-made structures. Nature has been using nanomaterials for millions of years,as Disckson has noted: “Life itself could be regarded as a nanophase system”.Examples in which nanostructured elements play a vital role are magnetotactic bacteria, ferritin, and molluscan teeth. Several species of aquatic bacteria use the earth’s magnetic field to orient thenselves. They are able to do this because they contain chains of nanosized, single-domain magnetite particles. Because they have established their orientation, they are able to swim down to nutriments and away from what is lethal to them ,oxygen. Another example of nanomaterials in nature is that herbivorous mollusks use teeth attached to a tonguelike organ, the radula, to scrape their food. These teeth have a complexstructure containing nanocrystalline needles. We can utilize biological templates formaking nanomaterials. Apoferritin has been used as a confined reaction environmentfor the synthesis of nanosized magnetite particles. Some scholars consider biologicalnanomaterials as model systems for developing technologically useful nanomaterials.Scientific work on this subject can be traced back over 100 years.In 1861 theBritish chemist Thomas Graham coined the term colloid to describe a solutioncontaining 1 to 100 nm diameter particles in suspension. Around the turn of thecentury, such famous scientists as Rayleigh, Maxwell, and Einstein studied colloids.In 1930 the Langmuir-Blodgett method for developing monolayer films wasdeveloped. By 1960 Uyeda had used electron microscopy and diffraction to studyindividual particles. At about the same time, arc, plasma, and chemical flame furnaceswere employed to prouduce submicron particles. Magnetic alloy particles for use inmagnetic tapes were produced in 1970.By 1980, studies were made on clusterscontaining fewer than 100 atoms .In 1985, a team led by Smalley and Kroto foundC clusters were unusually stable. In 1991, Lijima spectroscopic evidence that 60reported studies of graphitic carbon tube filaments.Research on nanomaterials has been stimulated by their technologicalapplications. The first technological uses of these materials were as catalysts andpigments. The large surface area to volume ratio increases the chemicalactivity.Because of this increased activity, there are significant cost advantages infabricating catalysts from nanomaterials. The peoperties of some single-phasematerials can be improved by preparing them as nanostructures. For example, thesintering temperature can be decreased and the plasticity increased on single-phase,structural ceramics by reducing the grain size to several nanometers. Multiphasenanostructured materials have displayed novel behavior resulting from the small sizeof he individual phases.Technologically useful properties of nanomaterials are not limited to theirstructural, chemical, or mechanical behavior. Multilayers represent examples ofmaterials in which one can modify of tune a property for a specific application bysensitively controlling the individual layer thickness. It was discovered that the resistance of Fe-Cr multilayered thin films exhibited large changes in an applied magnetic field of several tens of kOe.This effect was given the name giant magnetoresistance (GMR). More recently, suitably annealed magnetic multilayers have been developed that exhibit significant magnetoresistance effects even in fields as low as 5 to10 Oe (Oersted). This effect may prove to be of great technological importance for use in magnetic recording read heads.In microelectronics, the need for faster switching times and ever larger integration has motivated considerable effort to reduce the size of electronic components. Increasing the component density increases the difficulty of satisfying cooling requirements and reduces the allowable amount of energy released on switching between states. It would be ideal if the switching occurred with the motion of a single electron. One kind of single-electron device is based on the change in the Coulombic energy when an electron is added or removed from a particle. For a nanoparticle this enery change can be large enough that adding a single electron will effectively blocks the flow of other electrons. The use of Coulombic repulsion in this way is called Coulomb blockade.In addition to technology, nanomaterials are also interesting systems for basic scientific investigations .For example, small particles display deviations from bulk solid behavior such as reductios in the melting temperature and changes (usually reductions) in the lattice parameter. The changes n the lattice parameter observed for metal and semiconductor particles result from the effect of the surface free energy. Both the surface stress and surface free energy are caused by the reduced coordination of the surface atoms. By studying the size dependence of the properties of particles, it is possible to find the critical length scales at which particles behave essentially as bulk matter. Generally, the physical properties of a nanoparticle approach bulk values for particles containing more than a few hundred atoms.New techniques have been developed recently that have permitted researchers to produce larger quantities of other nanomaterials and to better characterize these materials.Each fabrication technique has its own set of advantages anddisadvantages.Generally it is best to produce nanoparticles with a narrow size distribution. In this regard, free jet expansion techniques permit the study of very small clusters, all containing the same number of atoms. It has the disadvantage of only producing a limited quantity of material.Another approach involves the production of pellets of nanostructured materials by first nucleating and growing nanoparticles in a supersaturated vapor and then using a cold finger to collect the nanoparticle. The nanoparticles are then consolidated under vacuum. Chemical techniques are very versatile in that they can be applied to nearly all materials (ceramics, semiconductors, and metals) and can usually produce a large amount of material. A difficulty with chemical processing is the need to find the proper chemical reactions and processing conditions for each material. Mechanical attrition, which can also produce a large amount of material, often makes less pure material. One problem common to all of these techniques is that nanoparticles often form micron-sized agglomerates. If this occurs, the properties of the material may be determined by the size of the agglomerate and not the size of the individual nanoparticles. For example, the size of the agglomerates may determine the void size in the consolidated nanostructured material.The ability to characterize nanomaterials has been increased greatly by the invention of the scanning tunneling microscope (STM) and other proximal probes such as the atomic force microscope (AFM), the magnetic force microscope, and the optical near-field microscope.SMT has been used to carefully place atoms on surfaces to write bits using a small number of atmos. It has also been employed to construct a circular arrangement of metal atoms on an insulating surface. Since electrons are confined to the circular path of metal atoms, it serves ad a quantum ‘corral’of atoms. This quantum corral was employed to measure the local electronic density of states of these circular metallic arrangements. By doing this, researchers were able to verify the quantum mechanical description of electrons confined in this way.Other new instruments and improvements of existing instruments are increasingly becoming important tools for characterizing surfaces of films, biological materials, and nanomaterials.The development of nanoindentors and the improvedability to interpret results from nanoindentation measurements have increased our ability to study the mechanical properties of nanostructured materials. Improved high-resolution electron microscopes and modeling of the electron microscope images have improved our knowledges of the structure of the the particles and the interphase region between particles in consolidated nanomaterials.Nanotechnology1. IntroductionWhat id nanotechnology? it is a term that entered into the general vocabulary only in the late 1970’s,mainly to describe the metrology associated with the development of X-ray,optical and other very precise components.We defined nanotechnology as the technology where dimensions and tolerances in the range 0.1~100nm(from the size of the atom to the wavelength of light) play a critical role.This definition is too all-embracing to be of practical value because it could include,for example,topics as diverse as X-ray crystallography ,atomic physics and indeed the whole of chemistry.So the field covered by nanotechnology is later narrowed down to manipulation and machining within the defined dimensional range(from 0.1nm to 100nm) by technological means,as opposed to those used by the craftsman,and thus excludes,for example,traditional forms of glass polishing.The technology relating to fine powders also comes under the general heading of nanotechnology,but we exclude observational techniques such as microscopy and various forms of surface analysis.Nanotechnology is an ‘enabling’ technology, in that it provides the basis for other technological developments,and it is also a ‘horizontal’or ‘cross-sectional’technology in that one technological may,with slight variations,be applicable in widely differing fields. A good example of this is thin-film technology,which is fundamental to electronics and optics.A wide range of materials are employed in devices such as computer and home entertainment peripherals, including magnetic disc reading heads,video cassette recorder spindles, optical disc stampers and ink jet nozzles.Optical and semiconductor components include laser gyroscope mirrors,diffraction gratings,X-ray optics,quantum-well devices.2. Materials technologyThe wide scope of nanotechnology is demonstrated in the materials field,where materials provide a means to an end and are not an end in themseleves. For example, in electronics,inhomogeneities in materials,on a very fine scale, set a limit to the nanometre-sized features that play an important part in semiconductor technology, and in a very different field, the finer the grain size of an adhesive, the thinner will be the adhesive layer, and the higher will be the bond strength.(1) Advantages of ultra-fine powders. In general, the mechanical, thermal, electrical and magnetic properties of ceramics, sintered metals and composites are often enhanced by reducing the grain or fiber size in the starting materials. Other properties such as strength, the ductile-brittle transition, transparency, dielectric coefficient and permeability can be enhanced either by the direct influence of an ultra-fine microstructure or by the advantages gained by mixing and bonding ultra-fine powders.Oter important advantages of fine powders are that when they are used in the manufacture of ceramics and sintered metals, their green (i.e, unfired) density can be greatly increased. As a consequence, both the defects in the final produce and the shrinkage on firing are reduced, thus minimizing the need for subsequent processing.(2)Applications of ultra-fine powders.Important applications include:Thin films and coatings----the smaller the particle size, the thinner the coating can beElectronic ceramics ----reduction in grain size results in reduced dielectric thicknessStrength-bearing ceramics----strength increases with decreasing grain sizeCutting tools----smaller grain size results in a finer cutting edge, which can enhance the surface finishImpact resistance----finer microstructure increases the toughness of high-temperature steelsCements----finer grain size yields better homogeneity and densityGas sensors----finer grain size gives increased sensitivityAdhesives----finer grain size gives thinner adhesive layer and higher bond strength3. Precision machining and materials processingA considerable overlap is emerging in the manufacturing methods employed in very different areas such as mechanical engineering, optics and electronics. Precision machining encompasses not only the traditional techniques such as turning, grinding, lapping and polishing refined to the nanometre level of precision, but also the application of ‘particle’ beams, ions, electrons and X-rays. Ion beams are capable of machining virtually any material and the most frequent applications of electrons and X-rays are found in the machining or modification of resist materials for lithographic purposes. The interaction of the beams with the resist material induces structural changes such as polymerization that alter the solubility of the irradiated areas.(1) Techniques1) Diamond turning. The large optics diamond-turning machine at the Lawrence Livermore National Laboratory represents a pinnacle of achievement in the field of ultra-precision machine tool engineering. This is a vertical-spindle machine with a face plate 1.6 m in diameter and a maximum tool height of 0.5m. Despite these large dimensions, machining accuracy for form is 27.5nm RMS and a surface roughness of 3nm is achievable, but is dependent both on the specimen material and cutting tool.(2) GrindingFixed Abrasive Grinding The term“fixed abrasive” denotes that a grinding wheel is employed in which the abrasive particles, such as diamond, cubic boron nitride or silicon carbide, are attached to the wheel by embedding them in a resin or a metal. The forces generated in grinding are higher than in diamond turning and usually machine tools are tailored for one or the other process. Some Japanese work is in the vanguard of precision grinding, and surface finishes of 2nm (peak-to-valley) have been obtained on single-crystal quartz samples using extremely stiff grinding machinesLoose Abrasive Grinding The most familiar loose abrasive grinding processes are lapping and polishing where the workpiece, which is often a hard material such asglass, is rubbed against a softer material, the lap or polisher, with abrasive slurry between the two surfaces. In many cases, the polishing process occurs as a result of the combined effects of mechanical and chemical interaction between the workpiece, slurry and polished.Loose abrasive grinding techniques can under appropriate conditions produce unrivalled accuracy both in form and surface finish when the workpiece is flat or spherical. Surface figures to a few nm and surface finishes bettering than 0.5nm may be achieved. The abrasive is in slurry and is directed locally towards the workpiece by the action of a non-contacting polyurethane ball spinning at high speed, and which replac es the cutting tool in the machine. This technique has been named “elastic emission machining” and has been used to good effect in the manufacture of an X-ray mirror having a figure accuracy of 10nm and a surface roughness of 0.5nm RMS.3)Thin-film production. The production of thin solid films, particularly for coating optical components, provides a good example of traditional nanotechnology. There is a long history of coating by chemical methods, electro-deposition, diode sputtering and vacuum evaporation, while triode and magnetron sputtering and ion-beam deposition are more recent in their wide application.Because of their importance in the production of semiconductor devices, epitaxial growth techniques are worth a special mention. Epitaxy is the growth of a thin crystalline layer on a single-crystal substrate, where the atoms in the growing layer mimic the disposition of the atoms in the substrate.The two main classes of epitaxy that have ben reviewed by Stringfellow (1982) are liquid-phase and vapour-phase epitaxy. The latter class includes molecular-beam epitaxy (MBE), which in essence, is highly controlled evaporation in ultra high vacuum. MBE may be used to grow high quality layered structures of semiconductors with mono-layer precision, and it is possible to exercise independent control over both the semiconductor band gap, by controlling the composition, and also the doping level. Pattern growth is possible through masks and on areas defined by electron-beam writing.4. ApplicationsThere is an all-pervading trend to higher precision and miniaturization, and to illustrate this a few applications will be briefly referred to in the fields of mechanical engineering,optics and electronics. It should be noted however, that the distinction between mechanical engineering and optics is becoming blurred, now that machine tools such as precision grinding machines and diamond-turning lathes are being used to produce optical components, often by personnel with a backgroud in mechanical engineering rather than optics. By a similar token mechanical engineering is also beginning to encroach on electronics particularly in the preparation of semiconductor substrates.(1) Mechanical engineeringOne of the earliest applications of diamond turning was the machining of aluminum substrates for computer memory discs, and accuracies are continuously being enhanced in order to improve storage capacity: surface finishes of 3nm are now being achieved. In the related technologies of optical data storage and retrieval, the toler ances of the critical dimensions of the disc and reading head are about 0.25 μm. The tolerances of the component parts of the machine tools used in their manufacture, i.e.the slideways and bearings, fall well within the nanotechnology range.Some precision components falling in the manufacturing tolerance band of 5~50nm include gauge blocks, diamond indenter tips, microtome blades, Winchester disc reading heads and ultra precision XY tables (Taniguchi 1986). Examples of precision cylindrical components in two very different fields, and which are made to tolerances of about 100 nm, are bearing for mechanical gyroscopes and spindles for video cassette recorders.The theoretical concept that brittle materials may be machined in a ductile mode has been known for some time. If this concept can be applied in practice it would be of significant practical importance because it would enable materials such as ceramics, glasses and silicon to be machined with minimal sub-surface damage, and could eliminate or substantially reduce the need for lapping and polishing.Typically, the conditions for ductile-mode machining require that the depth of cutis about 100 nm and that the normal force should fall in the range of 0.1~0.01N. These machining conditons can be realized only with extremely precise and stiff machine tools, such as the one described by Yoshioka et al (1985), and with which quartz has been ground to a surface roughness of 2 nm peak-to-valley. The significance of this experimental result is that it points the way to the direct grinding of optical components to an optical finish. The principle can be extended to other materials of significant commercial importance, such as ceramic turbine blades, which at present must be subjected to tedious surface finishing procedures to remove the structure-weakening cracks produced by the conventional grinding process.(2) OpticsIn some areas in optics manufacture there is a clear distinction between the technological approach and the traditional craftsman’s approach, particul arly where precision machine tools are employed. On the other hand, in lapping and polishing, there is a large grey area where the two approaches overlap. The large demand for infrared optics from the 1970s onwards could not be met by the traditional suppliers, and provided a stimulus for the development and application of diamond-turning machines to optic manufacture. The technology has now progressed and the surface figure and finishes that can be obtained span a substantial proportion of the nanotechnology range. Important applications of diamond-turned optics are in the manufacture of unconventionally shaped optics, for example axicons and more generelly, aspherics and particularly off-axis components. Such as paraboloids.The mass production(several million per annum) of the miniature aspheric lenses used in compact disc players and the associated lens moulds provides a good example of the merging of optics and precision engineering. The form accuracy must be better than 0.2μm and the surface roughness m ust be below 20 nm to meet the criterion for diffraction limited performance.(3) ElectronicsIn semiconductors, nanotechnology has long been a feature in the development of layers parallel to the substrate and in the substrate surface itself, and the need for precision is steadily increasing with the advent of layered semiconductor structures.About one quarter of the entire semiconductor physics community is now engaged in studying aspects of these structures. Normal to the layer surface, the structure is produced by lithography, and for research purposes ar least, nanometre-sized features are now being developed using X-ray and electron and ion-beam techniques.5. A look into the futureWith a little imagination, it is not difficult to conjure up visions of future developments in high technology, in whatever direction one cares to look. The following two examples illustrate how advances may take place both by novel applications and refinements of old technologies and by development of new ones.(1) Molecular electronicsLithography and thin-film technology are the key technologies that have made possible the continuing and relentless reduction in the size of integrated circuits, to increase both packing density and operational speed. Miniaturization has been achieved by engineering downwards from the macro to the micro scale. By simple extrapolation it will take approximately two decades for electronic switches to be reduced to molecular dimensions. The impact of molecular biology and genetic engineering has thus provided a stimulus to attempt to engineer upwards, starting with the concept that single molecules, each acting as an electronic device in their own right, might be assembled using biotechnology, to form molecular electronic devices or even biochip computers.Advances in molecular electronics by downward engineering from the macro to the micro scale are taking place over a wide front. One fruitful approach is by way of the Langmure-Biodgett (LB) film using a method first described by Blodgett (1935).A multi-layer LB structure consists of a sequence of organic monolayers made by repeatedly dipping a substrate into a trough containing the monolayer floating on a liquid (usually water), one layer being added at a time. The classical film forming materials were the fatty acids such as stearic acid and their salts. The late 1950s saw the first widespread and commercially important application of LB films in the field of X-ray spectroscopy (e.g, Henke 1964, 1965). The important properties of the films that were exploited in this application were the uniform thickness of each film, i.e.one molecule thick, and the range of thickness, say from 5to 15nm, which were available by changing the composition of the film material. Stacks of fifty or more films were formed on plane of curved substrates to form two-dimensional diffraction gratings for measuring the characteristic X-ray wavelengths of the elements of low atomic number for analytical purposes in instruments such as the electron probe of X-ray micro-analyzer.(2) Scanning tunneling engineeringIt was stated that observational techniques such as microscopy do mot, at least for the purposes of this article, fall within the domain of nanotechnology. However,it is now becoming apparent that scanning tunneling microscopy(STM) may provide the basis of a new technology, which we shall call scanning tunneling engineering.In the STM, a sharp stylus is positioned within a nanometre of the surface of the sample under investigation. A small voltage applied between the sample and the stylus will cause a current to foow through the thin intervening insulating medium (e.g.air, vacum, oxide layer). This is the tunneling electron current which is exponentially dependent on the sample-tip gap. If the sample is scanned in a planr parallel to ies surface and if the tunneling current is kept cnstant by adjusting the height of the stylus to maintain a constant gap, then the displacement of the stylus provides an accurate representation of the surface topographyu of the sample. It is relevant to the applications that will be discussed that individual atoms are easily resolved by the STM, that the stylus tip may be as small as a single atom and that the tip can be positioned with sub-atomic dimensional accuracy with the aid of a piezoelectric transducer.The STM tip has demonstrated its ability to draw fine lines, which exhibit nanometre-sized struture, and hence may provide a new tool for nanometre lithography.The mode of action was not properly understood,but it was suspected that under the influence of the tip a conducting carbon line had been drawn as the result of polymerizing a hydrocarbon film, the process being assisted by the catalytic activity of the tungsten tip. By extrapolating their results the authors believed that it would be possible to deposit fine conducting lines on an insulating film. The tip would operatein a gaseous environment that contained the metal atoms in such a form that they could either be pre-adsorbed on the film or then be liberated from their ligands or they would form free radicals at the location of the tip and be transferred to the film by appropriate adjustment of the tip voltage.Feynman proposed that machine tools be used to make smaller machine tools which in turn would make still smaller ones, and so on all the way down to the atomic level. These machine tools would then operate via computer control in the nanometre domain, using high resolution electron microscopy for observation and control. STM technology has short-cricuired this rather cumbrous concept,but the potential applications and benefits remain.原文(二)Micro-machine1. IntroductionFrom the beginning, mankind seems instinctively to have desired large machines and small machines. That is, “large” and “small” in comp arison with human-scale. Machines larger than human are powerful allies in the battle against the fury of nature; smaller machines are loyal partners that do whatever they are told.If we compare the facility and technology of manufacturing larger machines, common sense tells us that the smaller machines are easier to make. Nevertheless, throughout the history of technology, larger machines have always stood ort. The size of the restored models of the water-mill invented by Vitruvius in the Roman Era, the windmill of the middle Ages, and the steam engine invented by Watt is overwhelming. On the other hand, smaller machined in history of technology are mostly tools. If smaller machines are easier to make, a variety of such machined should exist, but until modern times, no significant small machines existed except for guns and clocks.This fact may imply that smaller machines were actually more difficult to make. Of course, this does not mean simply that it was difficult to make a small machine; it means that it was difficult to invent a small machine that would be significant to human beings.。
聚合物纳米技术
Cleaning Applications
Nano titanium dioxide particles; energy in light to start the chemical reaction that kills the bacteria. Nano colloidal micelles make a better soap. Coated nanofilms provide certain surface characteristics
聚合物奈米技術 Polymer Nano-technology
蘇添貴(Tien-Kuei Su) 貴瑩公司顧問
聚合物奈米技術 Polymer Nano-technology
Background Type of Nanostructures Fabrication Techniques Applications/Benefits - Nanoclay in Packagings Potential Issues
Fabrication Techniques Pores/Voids, Nanofibers
Solvent followed by evaporization, extraction. Change of morphology, phase Additives; nanostructures (US 7115680), X-link (US 7067058,6039872) Incompatible blends Stretching/Orientation Fibrillation Others
- 金屬納米粒子是由化學方法先獲得,然後,分發 (Disperse)到聚合物溶液(Polymer Solution)或 單體溶液聚合
aao模板法制备纳米材料流程
aao模板法制备纳米材料流程The preparation of nano-materials using the aao template method is a complex and fascinating process. 运用aao模板法制备纳米材料是一个复杂而迷人的过程。
This method involves the use of an anodic aluminum oxide (AAO) template to create nanoscale structures with precise control over size and shape. 这种方法涉及使用阳极氧化铝(AAO)模板,以精确控制尺寸和形状创建纳米级结构。
The AAO template acts as a scaffold for the growth of nanostructures, allowing for the precise arrangement of atoms and molecules at the nanoscale. AAO模板作为纳米结构生长的支架,允许在纳米尺度上精确排列原子和分子。
This process holds great potential for the development of advanced materials with unique properties and applications in various fields. 这一过程在开发具有独特性能和在各个领域应用的先进材料方面具有巨大潜力。
One of the key steps in the AAO template method is the fabrication of the AAO template itself. AAO模板方法的关键步骤之一是AAO模板本身的制备。
This involves the anodization of aluminum to create a porous oxide layer with highly ordered, hexagonally arranged nanopores. 这涉及对铝进行阳极氧化,形成高度有序的六边形排列的纳米孔的多孔氧化物层。
纤维素模板法制备多孔碳纳米棒及其超级电容器性能(英文)
Porous carbons have potential applications in rubber additives,gas separation,catalysis and energystorage[1]. For a variety of practical applications,the fabrication of desired morphologies is important as well as the control of composition,structure and porosity. Herein we report the facile fabrication of porous carbon nanorods based on atom transfer radical polymerization ( ATRP ) process by using cellulose brushes as template. The schematic procedure for the preparation of porous carbon nanorods was shown in Fig 1. The fabrication of porous carbon nanorods was schematically illustrated in Fig 1. Cellulose was completely dissolved in ionic liquid to form homogeneous solution using 1-allyl-3-methylimidazolium chloride as the solvent [Fig 1 ( a) ][2]. Then cellulose-macroinitiator was prepared by esterification using 2-bromoisobutyryl bromide[Fig 1( b) ]. Cellulose-g-polyacrylonitrile( cellulose-g-PAN) brushes were synthesized by ATRP method [Fig 1( c) ],followed by thermal stabilization and carbonization under nitrogen atmosphere to obtain the nanostructured carbonrods[Fig 1 ( d) ].
电化学沉积制备氧化钼_碳纳米管复合纤维及其电化学行为_温洋洋
硅酸盐学报· 1220 ·2012年电化学沉积制备氧化钼/碳纳米管复合纤维及其电化学行为温洋洋1,钟小华1,洪英哲1,2,李亚利1(1. 天津大学材料科学与工程学院,先进陶瓷及加工技术教育部重点实验室,中国天津 300072;2. 金策工业综合大学,朝鲜平壤 999093)摘要:以电化学沉积法将氧化钼(MoO x)沉积于宏观碳纳米管(CNT)纤维上,制得氧化钼包覆碳纳米管复合纤维(MoO x/CNT),研究了复合纤维的结构、相组成及电化学性能。
结果表明:该复合纤维由氧化钼均匀包覆碳纳米管束的同轴纳米纤维构成,氧化钼包覆层厚度为100~175nm,碳纳米管束直径为20~60nm,能谱分析表明包覆层含Mo和O;将该复合纤维用于电化学系统超电容,电化学测试其具有明显的电化学活性,电容量为19F/g;该复合纤维可用于发展电化学功能纤维或编织储能器件。
关键词:氧化钼;碳纳米管;纤维;电化学沉积中图分类号:TB332 文献标志码:A 文章编号:0454–5648(2012)08–1220–04网络出版时间:2012–07–30 13:23:34 网络出版地址:/kcms/detail/11.2310.TQ.20120730.1323.201208.1220_023.html Fabrication of Molybdenum Oxides/Carbon Nanotube Composite Fibers byElectrochemical Deposition and its Electrochemical BehaviorWEN Yangyang1,ZHONG Xiaohua1,HONG Yingzhe1,2,LI Yali1(1. Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University,Tianjin 300072, China; 2. Kim Chaek University of Technology, Pyongyang 999093, North Korea)Abstract: Molybdenum oxide/carbon nanotube (MoO x/CNT) composite fibers were fabricated via the electrochemical deposition of MoO x on macroscopic carbon nanotube fibers spun from a chemical vapor deposition process. The observation by scanning electron microscopy shows that the composite fiber consists of unique core-shell axial nanofibers. The thickness of MoO x layer is 100–175nm and the CNT core is 20–60nm. The electrochemical properties of the composite fibers were examined in the aqueous electrolyte, showing a distinct electrochemical response with a capacitance of 19F/g. This functional oxide and CNT composite fiber have some potential applications as a multifunctional electric supercapacitor for the development of weaving fabrics.Key words: molybdenum oxide; carbon nanotube; fibers; electrochemical deposition碳纳米管(CNT)具有一维纳米结构、高比表面积、高导电性和优异的力学性能[1–3]。
[2016学位论文].以卟啉基金属聚合物为前体合成多功能磁性纳米材料及其应用..
『毕业论文社区』优质论文硕博学位论文1/79太原理工大学硕士研究生学位论文I以卟啉基金属聚合物为前体合成多功能磁性纳米材料及其应用研究摘 要金属纳米材料由于其纳米级尺寸而具有很多独特的物化特性,从而引起了众多科研人员的广泛关注。
金属纳米粒子已经在很多领域得到广泛应用,如永磁体,高密度磁存储器件,磁共振成像,药物运输,生物传感器,可回收催化剂等。
近年来,科研人员又通过一些新方法将其应用到一些新兴领域,如以异核双金属聚合物为前体,通过纳米压印和高温热解的方法,制备磁性金属合金纳米阵列结构,从而实现高密度信息垂直磁记录;另外,由于金属纳米粒子的磁性质和表面等离子效应,科研人员通过将金属纳米粒子掺杂到OLED 和太阳能电池功能层中,有效地改善了器件性能。
其中需要特别说明的是,由于金属合金纳米粒子具有独特的组成和结构使其具有一些单金属不具备的性能。
就金属合金纳米粒子的制备方法来说,主要通过将含不同金属的前体物理混合后,通过高温可控分解来制备合金纳米粒子,但这种方法制备的纳米粒子粒径不可控且不稳定,也容易发生团聚、烧结等问题。
本论文设计并合成一系列异核双金属聚合物和单核金属聚合物,并以这些聚合物或者其混合体为前体,利用纳米压印光刻技术制备位元规则介质,用于信息高密度磁存储体系;同时也将以所合成的金属聚合物为单一前体,通过高温可控分解的方法制备表面碳包覆的磁性纳米粒子,再尝试将这些磁性纳米粒子掺杂到OLED 中,探究其在OLED 中的应用和作用机制。
本论文主要研究内容如下:(1)设计并合成卟啉基金属聚合物。
在这里,我们利用卟啉化合物的模板效应,合成一系列金属卟啉化合物(DETPP-Fe, DETPP-Co 和DETPP-Ni ),同时合成了含金属Pt 的配体和芴基配体,最后,通过将金属卟啉化合物和这些配体分别进行偶联反应,合成了一系列卟啉基异核双金属聚合物(DETPP-P-FePt ,DETPP-P-CoPt 和DETPP-P-NiPt )和单核金属聚合物(DETPP-P-Fe ,DETPP-P-Co 和DETPP-P-Ni)。
表面修饰纳米二氧化硅及其与聚合物的作用
万方数据 万方数据第lo期束华东等表面修饰纳米二氧化硅及其与聚合物的作用条件,如一COOH、一NcO和一CHcH:0等,以保证修饰的稳定性。
Tang等m1和Ding等汹1在各自的工作中都用油酸修饰纳米SiO:,修饰剂以稳定的化学键与纳米颗粒连接,同时油酸上带有的C—C又为SiO:提供了表面功能化的基团。
此外,乙烯基吡啶协1、丙烯基缩水甘油醚m1和对乙烯基苯磺酰肼Ⅲ1等用作纳米sj02表面修饰剂的工作都有报道。
在我们以前的工作中,用六甲基二硅氮烷作为修饰剂合成了具有超强疏水性能的可分散型纳米SiO:颗粒,涂层与水的接触角可达1700,同时在有机溶剂中有良好的分散性,分散在co,中溶液的透光率可达97%以上旧J。
还有用乙二胺和硬脂酸对纳米SiO:颗粒表面双重修饰,这是一种以离子键连接表面修饰剂和纳米颗粒的修饰方式,产物的粒径在20nm左右mo。
此外,我们还利用不同的硅烷偶联剂合成了表面带有不同官能团的可反应性纳米SiO,颗粒b“。
目前,我们所开发的上述产品已经在本单位的纳米材料工程技术研究中心实现了规模化生产。
图3为生产的DNS.2可分散型纳米SiO,的透射电镜形貌,从图中可以看出纳米SiO,颗粒粒径均匀,平均约20nm,分散优良,以链状或网状存在。
图3DNS-2可分散型纳米si02的TEM形貌Fig.3TEMimageofthedispersiblenllllO—Si022纳米SiO:颗粒与聚合物基体的作用方式及其对材料性能的影响聚合物/SiO:纳米复合材料能有效地综合利用纳米si02和聚合物材料的各项优越性能,使材料的功能多样化,性能优越化。
纳米SiO,与聚合物基体的复合方法主要包括:机械共混法、熔融共混法、溶胶.凝胶法和原位分散聚合法等。
不同的复合方法各有其优点,适用于不同的材料,对纳米颗粒和基体材料的作用方式也有着不同的影响。
在聚合物/SiO:纳米复合材料中,纳米颗粒与聚合物基体间作用力的形式和大小对材料的性能会产生较大的影响,提高二者间的作用力是提升材料性能的主要手段。
Cover Letter(投稿信)-建议往重要期刊投稿时使用-喻海良
Chief EditorScientific ReportsThe Macmillan Building4 Crinan StreetLondon N19XW, UKDear Editor:Please find attached our manuscript entitled “A new insight into ductile fracture of ultrafine-grained Al-Mg alloys” which we wish to submit for possible publication in Scientific Reports. This manuscript, or any part of it, has not been published and will not be submitted elsewhere for publication while being considered by Scientific Reports. The manuscript has not been discussed with a Scientific Reports Editor prior to submission. The authors declare that there are no competing financial interests.The authors have a collective research background unifying nanoscale materials, metals and alloys, composite materials, fracture and damage mechanics, applied physics, and mechanical properties. In the current study, we have discovered a relationship between the ductile fracture mechanism and grain refinement of ultrafine-grained/nanostructured metals. We found that the mean grain size at fracture end approaches the theoretical minimum achievable mean grain size value that directly determines the fracture behavior of metals post necking. This finding will be a milestone in fracture mechanics and nanostructured materials. Thus this work will be of great interest to readers of various scientific disciplines, in particular materials scientists and physicists working on nanostructured materials as well as micromechanics.In the past 50 years, many ductile fracture criteria have been proposed. The basic principles upon which ductile fracture criteria are based can be generally divided into four categories: (a) energy dissipation; (b) void growth: material modeling; (c) void growth: growth mechanisms; and (d) void growth: void geometry. It is assumed that the fracture evolution directly depends on the strength, strain hardening capability and strain rate sensitivity of the matrix surrounding the voids. None of these criteria are related to the microstructure change in ductile fracture processing. In the current study, it is proposed for the first time that features of the microstructure near the fracture surface can be used to explain the ductile fracture post necking directly. We found that grains are refined to nanoscale approaching the theoretical minimum achievable value and become brittle in the shear band zone. As explained in the paper, the observation suggested the innovative five-step ductile fracture mechanism: uniform elongation, void nucleation and growth, local necking, grain refinement until the mean grain size approaches the minimum achievable mean grain size, and finally damage.The corresponding author is Dr. Hailiang Yu, School of Mechanical, Materials and Mechatronics Engineering, University of Wollongong, Wollongong, Australia, contactable by email address hailiang@.au or yuhailiang1980@. The primary work telephone number is +61 (04) 2505 5006 and fax number is +61 (02) 4221 5474.Thank you for your kind consideration.近年笔者发表的主要论文1.Yu H.L.*, Tieu K., Lu C., Liu X., Liu M., Godbole A., Kong C., Qin Q.H. A new insightinto ductile fracture of ultrafine-grained Al-Mg alloys. Scientific Reports, 2015, 5: 9568.Free access available from: /10.1038/srep095682.Yu H.L.*, Tieu K., Hadi S., Lu C., Godbole A., Kong C. High strength and ductility ofultrathin laminate foils using accumulative roll bonding and asymmetric rolling.Metallurgical and Materials Transactions A, 2015, 46: 869-879.Available from: /10.1007/s11661-014-2640-33.Yu H.L.*, Tieu K., Lu C., Kong C. Abnormally high residual dislocation density in purealuminum after Al/Ti/Al laminate annealing for seven days. Philosophical Magazine Letters, 2014, 94: 732-740.Free access available from: /10.1080/09500839.2014.9719024.Yu H.L.*, Tieu K., Lu C., Lou Y.S., Liu X.H., Godbole A., Kong C. Tensile fracture ofultrafine Al 6061 sheets by asymmetric cryorolling for microforming. International Journal of Damage Mechanics, 2014, 23: 1077-1095.Available from: /10.1177/10567895145380835.Yu H.L.*, Tieu K., Lu C., Liu X., Godbole A., Li H.J., Kong C., Qin Q.H. A deformationmechanism of hard metal surrounded by soft metal during roll forming. Scientific Reports, 2014, 4: 5017.Free access available from: /10.1038/srep050176.Yu H.L.*, Tieu K., Lu C., Godbole A. An investigation of interface bonding of bimetallicfoils by combined accumulative roll bonding and asymmetric rolling techniques.Metallurgical and Materials Transactions A, 2014, 45: 4038-4045.Available from: /10.1007/s11661-014-2311-47.Yu H.L.*, Liu X.H., Li X.W., Godbole A. Crack healing in a low-carbon steel under hotplastic deformation. Metallurgical and Materials Transactions A, 2014, 45, 1001-1009.Available from: /10.1007/s11661-013-2049-48.Yu H.L.*, Lu C., Tieu K., Godbole A., Sun Y., Liu M., Su L.H., Tang D.L., Kong C.Fabrication of ultrathin nanostructured bimetal foils by accumulative roll bonding and asymmetric rolling.Scientific Reports, 2013, 3: 2373.Free access available from: /10.1038/srep023739.Yu H.L.*, Tieu K. Lu C., Liu X.H., Godbole A., Kong C. Mechanical properties ofAl-Mg-Si alloy sheets produced using asymmetric cryorolling and ageing treatment.Materials Science Engineering A, 2013, 568: 212-218.Available from: /10.1016/j.msea.2013.01.04810.Y u H.L.*, Lu C., Tieu K., Liu X.H., Sun Y., Yu Q.B., Kong C. Asymmetric cryorollingfor fabrication of nanostructural aluminum sheets,Scientific Reports, 2012, 2: 772.Free access available from: DOI: /10.1038/srep00772*******如果您不能下载全文,请通过hailiang@.au联系*******。
材料科学与工程专业英语匡少平课后翻译答案精编WORD版
材料科学与工程专业英语匡少平课后翻译答案精编W O R D版IBM system office room 【A0816H-A0912AAAHH-GX8Q8-GNTHHJ8】Alloy合金applied force作用力amorphous materials不定形材料artificial materials人工材料biomaterials生物材料biological synthesis生物合成biocompatibility生物相容性brittle failure脆性破坏carbon nanotub e碳纳米管carboxylic acid羟酸critical stress临近应力dielectric constant介电常数clay minera l粘土矿物cross-sectional area横截面积critical shear stress临界剪切应力critical length临界长度curing agent固化剂dynamic or cyclic loading动态循环负载linear coefficient of themal expansio n性膨胀系数electromagnetic radiation电磁辐射electrodeposition电极沉积nonlocalizedelectrons游离电子electron beam lithography电子束光刻elasticity 弹性系数electrostation adsorption静电吸附elastic modulus弹性模量elastic deformation弹性形变elastomer弹性体engineering strain工程应变crystallization 结晶fiber-optic光纤维Ethylene oxide环氧乙烷fabrication process制造过程glass fiber玻璃纤维glass transition temperature 玻璃化转变温度heat capacity热熔Hearing aids助听器integrated circuit集成电路Interdisplinary交叉学科intimate contact密切接触inert substance惰性材料implant移植individual application个体应用deformation局部形变mechanical strength机械强度mechanical attrition机械磨损Mechanical properties力学性Materials processing材料加工质mechanical behavior力学行为magnetic permeability磁导率magnetic hybrid technique混合技术induction磁感应mass per unit of volume单位体积质量monomer identity单体种类molecular mass分子量microsphere encapsulation technique微球胶囊技术macroscopical宏观的naked eye 肉眼nonlocalized nanoengineered materials纳米材料nanostructured materials纳米结构材料nonferrous metal有色金属线nucleic acid核酸nanoscale纳米尺度Nanotechnology纳米技术nanobiotechnology纳米生物技术nanocontact printing纳米接触印刷optical property光学性质optoelectronic device光电设备oxidation degradation 氧化降解piezoelectric ceramics压电陶瓷Relative density相对密度stiffnesses刚度sensor传感材料semiconductors半导体specific gravity比重shear 剪切Surface tention表面张力self-organization自组装static loading静载荷stress area应力面积stress-strain curves应力应变曲线sphere radius球半径submicron technique亚微米技术substrate衬底supramolecalar超分子sol-gel method溶胶凝胶法thermal/electrical conductivity 热/点导率thermoplastic materials热塑性材料Thermosetting plastic热固性塑料thermal motion热运动toughness test韧性试验tension张力torsion扭曲Tensile Properties拉伸性能Two-dimentional nanostructure二维纳米结构Tissue engineering组织工程transplantation of organs器官移植the service life使用寿命the longitudinal direction纵向the initial length of the materials初始长度the acceleration gravity重力加速度the normal vertical axis垂直轴the surface to volume ratio 比表面密度the burgers vector伯格丝矢量the mechanics and dynamics of tissues 组织力学和动力学phase transformation temperature相转变温度plastic deformation塑性形变Pottery陶瓷persistence length余晖长度polymer synthesis聚合物合成Polar monomer记性单体polyelectrolyte高分子电解质pinning point钉扎点plasma etching 等离子腐蚀pharmacological acceptability药理接受性pyrolysis高温分解ultrasonic treatment超射波处理yield strength屈服强度vulcanization硫化1-1:直到最近,科学家才终于了解材料的结构要素与其特性之间的关系。
纳米金技术标准
纳米金技术标准Nanogold technology is a cutting-edge field with the potential to revolutionize various industries, from healthcare to electronics. The standardization of nanogold technology is crucial to ensure its safety, effectiveness, and compatibility across different applications. Standard protocols and guidelines for the synthesis, characterization, and application of nanogold materials can help researchers and industries develop consistent and reliable products.纳米金技术是一个前沿领域,有潜力彻底改变各个行业,从医疗保健到电子。
纳米金技术的标准化对于确保其安全性、有效性和在不同应用中的兼容性至关重要。
对纳米金材料的合成、表征和应用制定标准化协议和指导方针可以帮助研究人员和行业开发一致且可靠的产品。
In the healthcare industry, nanogold technology holds great promise for improving diagnostic techniques, drug delivery systems, and cancer treatment. Standardized protocols for the production of nanogold-based contrast agents for imaging purposes can enhance the accuracy and reliability of medical imaging. Moreover, nanogold particles can serve as targeted drug carriers, delivering therapeuticagents directly to cancer cells while minimizing side effects on healthy tissues.在医疗保健行业,纳米金技术对于改善诊断技术、药物递送系统和癌症治疗具有巨大潜力。
管状氧化锌
Cite this: J. Mater. Chem. A, 2013, 1, 814
Porous ZnO microtubes with excellent cholesterol sensing and catalytic properties†
Arnab Kanti Giri, Apurba Sinhamahapatra, S. Prakash, Jayesh Chaudhari, Vinod Kumar Shahi* and Asit Baran Panda‡*
Received 29th August 2012 Accepted 19th October 2012 DOI: 10.1039/c2ta00107a /MaterialsA
Introduction
The development of novel nanostructured metal oxides with varying sizes and shapes has stimulated remarkable research interest in recent frontier research of their novel size- and shape-dependent properties and tailorable functionalities.1 Particularly, porous structures with varying morphologies are in the spot light due to their ir high porosity; they exhibit unique physicochemical properties compared to their non-porous analogues, and are important materials for technological applications such as catalysis, sensing, Li-ion battery electrodes, solar cells, and so on.2
nanoscale投稿模板
nanoscale投稿模板篇一:Cover Letter(投稿信)-建议往重要期刊投稿时使用Chief EditorScientific ReportsThe Macmillan Building4 Crinan StreetLondon N19XW, UKDear Editor:Please find attached our manuscript entitled “A new insight into ductile fracture of ultrafine-grained Al-Mg alloys” which we wish to submit for possible publication in Scientific Reports. This manuscript, or any part of it, has not been published and will not be submitted elsewhere for publication while being considered by Scientific Reports. The manuscript has not been discussed with a Scientific Reports Editor prior to submission. The authors declare that there are no competing financial interests.The authors have a collective research background unifying nanoscale materials, metals and alloys, composite materials, fracture and damage mechanics, applied physics, and mechanical properties. In the current study, we have discovered a relationship between the ductile fracture mechanism and grain refinement of ultrafine-grained/nanostructured metals. We found that the mean grain size at fracture end approaches the theoretical minimum achievable mean grain size value that directly determines the fracture behavior of metals post necking. This finding will be a milestone in fracture mechanics and nanostructured materials. Thus this work will be of great interest to readers of various scientific disciplines, in particular materials scientists and physicists working on nanostructured materials as well as micromechanics.In the past 50 years, many ductile fracture criteria have been proposed. The basic principles upon which ductile fracture criteria are based can be generally divided into four categories: (a) energy dissipation; (b) void growth: material modeling; (c) void growth: growth mechanisms; and (d) void growth:void geometry. It is assumed that the fracture evolution directly depends on the strength, strain hardening capability and strain rate sensitivity of the matrix surrounding the voids. None of these criteria are related to the microstructure change in ductile fracture processing. In the current study, it is proposed for the first time that features of the microstructure near the fracture surface can be used to explain the ductile fracture post necking directly. We found that grains are refined to nanoscale approaching the theoretical minimum achievable value and become brittle in the shear band zone. As explained in the paper, the observation suggested the innovative five-step ductile fracture mechanism: uniform elongation, void nucleation and growth, local necking, grain refinement until the mean grain size approaches the minimum achievable mean grain size, and finally damage.The corresponding author is Dr. Hailiang Yu, School of Mechanical, Materials and Mechatronics Engineering, University of Wollongong, Wollongong, Australia, contactable by email address or . Theprimary work telephone number is +61 (04) 2505 5006 and fax number is +61 (02) 4221 5474.Thank you for your kind consideration.近年笔者发表的主要论文1. Yu *, Tieu K., Lu C., Liu X., Liu M., GodboleA., Kong C., Qin A new insight into ductile fracture of ultrafine-grained Al-Mg alloys. Scientific Reports, XX, 5: 9568. Free access available from:2. Yu *, Tieu K., Hadi S., Lu C., Godbole A., KongC. High strength and ductility of ultrathin laminate foils using accumulative roll bonding and asymmetric rolling. Metallurgical and Materials Transactions A, XX, 46: 869-879.Available from:3. Yu *, Tieu K., Lu C., Kong C. Abnormally high residual dislocation density in pure aluminum after Al/Ti/Al laminate annealing for seven days. Philosophical Magazine Letters, XX, 94: 732-740.Free access available from:4. Yu *, Tieu K., Lu C., Lou , Liu , Godbole A., Kong C. Tensile fracture of ultrafine Al 6061 sheets by asymmetric cryorolling for microforming. International Journal of Damage Mechanics, XX, 23: 1077-1095.Available from:5. Yu *, Tieu K., Lu C., Liu X., Godbole A., Li , Kong C., Qin A deformation mechanism of hard metal surrounded by soft metal during roll forming. Scientific Reports, XX, 4: 5017.Free access available from:6. Yu *, Tieu K., Lu C., Godbole A. An investigation of interface bonding of bimetallic foils by combined accumulative roll bonding and asymmetric rolling techniques. Metallurgical and Materials Transactions A, XX, 45: 4038-4045.Available from:7. Yu *, Liu , Li , Godbole A. Crack healing ina low-carbon steel under hot plastic deformation. Metallurgical and Materials Transactions A, XX, 45,1001-1009. Available from:8. Yu *, Lu C., Tieu K., Godbole A., Sun Y., Liu M., Su , Tang , Kong C. Fabrication of ultrathin nanostructured bimetal foils by accumulative roll bonding and asymmetric rolling. Scientific Reports, XX, 3: 2373.Free access available from:9. Yu *, Tieu K. Lu C., Liu , Godbole A., Kong C. Mechanical properties of Al-Mg-Si alloy sheets produced using asymmetric cryorolling and ageing treatment. Materials Science Engineering A, XX, 568: 212-218.Available from:10. Yu *, Lu C., Tieu K., Liu , Sun Y., Yu , KongC. Asymmetric cryorolling for fabrication of nanostructural aluminum sheets, Scientific Reports, XX, 2: 772. Free access available from: DOI:*******如果您不能下载全文,请通过联系******* 篇二:国外期刊投稿指南国外期刊投稿指南1. 1 投稿的方式投稿主要有三种方式:纸质投稿、EMAIL投稿和网上投稿。
四氧化三铁——精选推荐
四氧化三铁共沉淀法制备四氧化三铁纳⽶磁性材料引⾔:磁性是物质的基本属性,磁性材料是古⽼⽽⽤途⼗分⼴泛的功能材料。
磁挂材料与信息化、⾃动化、机电⼀体化、国防、国民经济的⽅⽅⾯⾯紧密相关.纳⽶磁性材料是20世纪70年代后逐步产⽣、发展,壮⼤⽽成为最富有竞争⼒与宽⼴应⽤前景的新型磁性材料。
纳⽶磁性材料的特性不同于常规的磁性材料,其原因是与磁相关联的特征物理长度恰好处于纳⽶量级,倒如:磁单畴临界尺⼨,超顺磁性临界尺⼨,交换作⽤长度以及电⼦平均⾃由路程等⼤致上处于l~1OOnm量级,当磁性体的尺⼨与这些特征物理长度相当时就会呈现反常的磁学性质[1]。
磁性纳⽶材料除具有纳⽶材料的⼀般特性外还具有顺磁效应,其中Fe3O4纳⽶晶由于其超顺磁性、⾼表⾯活性等特性,已在磁流体、微波吸收、⽔处理、光催化、⽣物医药、⽣物分离等⽅⾯得到了⼴泛的应⽤,正在成为磁性纳⽶材料的研究热点。
⽬前制备磁性Fe3O4纳⽶晶的主要⽅法有沉淀法、溶剂热法、溶胶-凝胶法、微乳液法、微波超声法等[2-8],这⼏种⽅法制得的磁性Fe3O4纳⽶晶在结构和性能⽅⾯都有⼀定的差异,因此在不同领域的应⽤往往要采⽤不同的制备⽅法。
其中共沉淀法即在含有两种或两种以上阳离⼦的可溶性溶液中加⼊适当的沉淀剂,使⾦属离⼦均匀沉淀或结晶出来,再将沉淀物脱⽔或热分解⽽制得纳⽶微粉。
共沉淀法有两种: ⼀种是Massart ⽔解法[9],即将⼀定摩尔⽐的三价铁盐与⼆价铁盐混合液直接加⼊到强碱性⽔溶液中, 铁盐在强碱性⽔溶液中瞬间⽔解结晶形成磁性铁氧体纳⽶粒⼦。
另⼀种为滴定⽔解法[10], 是将稀碱溶液滴加到⼀定摩尔⽐的三价铁盐与⼆价铁盐混合溶液中, 使混合液的pH 值逐渐升⾼, 当达到6~7 时⽔解⽣成磁性Fe3O4纳⽶粒⼦共沉淀⽅法的最⼤优点是设备要求低、成本低、操作简单和反应时间短,便于在实验室内操作。
本⽂主要介绍共沉淀法合成纳⽶Fe3O4及浓度、熟化时间、pH、超声波对纳⽶Fe3O4粒径等性质的影响。
小作文纳米技术英语
小作文纳米技术英语Nano technology, a field of science and engineeringthat deals with the manipulation of matter at the atomic and molecular scale, has garnered significant attention and investment in recent years. Its applications span various industries, including medicine, electronics, energy, and materials science. In this essay, we will delve into the advancements, challenges, and future prospects of nanotechnology.Firstly, let's explore the advancements in nanotechnology. One of the remarkable achievements is the development of nanomedicine, where nanoparticles are used for targeted drug delivery, imaging, and therapy. These nanoparticles can be engineered to selectively bind to specific cells or tissues, allowing for precise treatment with minimal side effects. Additionally, nanotechnology has revolutionized the field of electronics through the fabrication of nanoscale transistors and memory devices, enabling faster and more energy-efficient electronicdevices.Moreover, nanotechnology has opened up newpossibilities in renewable energy. Nanostructured materials, such as quantum dots and nanowires, have shown promise in enhancing the efficiency of solar cells and fuel cells. By harnessing the unique properties of nanomaterials, researchers aim to overcome existing limitations in energy conversion and storage technologies.However, along with these advancements come several challenges that need to be addressed. One of the primary concerns is the potential environmental and health risks associated with nanomaterials. Due to their small size and large surface area, nanoparticles may exhibit unique toxicological properties that are not observed in larger particles of the same material. Therefore, it is crucial to thoroughly assess the safety of nanoproducts before their widespread commercialization.Furthermore, the scalability of nanomanufacturing processes remains a significant hurdle. While researchershave demonstrated the fabrication of nanoscale structuresin laboratories, scaling up production to industrial levels without compromising quality and cost-effectiveness is a daunting task. Innovations in nanofabrication techniques, such as nanoimprint lithography and self-assembly, are being pursued to address this challenge.Looking ahead, the future of nanotechnology appears promising with ongoing research efforts and technological advancements. In the field of medicine, nanorobotics holds the potential for precise manipulation and delivery of drugs at the cellular level, paving the way for personalized medicine and targeted cancer therapies. Moreover, the integration of nanoelectronics withbiological systems could lead to the development of advanced prosthetics, neural implants, and brain-computer interfaces, revolutionizing healthcare and human-machine interactions.In conclusion, nanotechnology represents a frontier of scientific exploration with vast potential to transform various aspects of our lives. While significant progresshas been made in harnessing the unique properties of nanomaterials, challenges such as safety, scalability, and ethical considerations persist. By addressing these challenges through interdisciplinary collaboration and responsible innovation, we can unlock the full benefits of nanotechnology and usher in a new era of technological advancement.。
用纳米做的翅膀英语作文
用纳米做的翅膀英语作文Nano-engineered Wings: Mimicking Nature's Flight.The realm of flight has fascinated humans for centuries, inspiring countless innovations and scientific advancements. While traditional aircraft have enabled us to soar through the skies, the quest for more efficient and sustainable modes of aerial locomotion continues to push the boundaries of engineering and materials science. In recent years, the advent of nanotechnology has opened up new possibilitiesfor the design and fabrication of ultra-lightweight, high-performance wings.Biomimicry and Nature's Inspiration.Nature has long been a source of inspiration for engineers, particularly in the field of flight. Birds and insects, with their remarkable aerial abilities, have evolved intricate wing structures that allow them toachieve exceptional maneuverability, speed, and energyefficiency. By studying these biological counterparts, scientists have gained valuable insights into the design principles that underpin efficient flight.One of the key lessons learned from nature is the importance of low weight and high strength. Birds, for instance, possess lightweight bones and hollow structures that minimize weight while maintaining structural integrity. Insects, on the other hand, utilize a layered cuticlesystem that combines strength and flexibility. Thesenatural designs have served as blueprints for the development of nano-engineered wings.Materials for Nano-winged Flight.The emergence of nanomaterials has provided engineers with a new palette of materials to work with. Carbon nanotubes, graphene, and other nanomaterials possess exceptional strength-to-weight ratios and extraordinary mechanical properties. These materials can be manipulatedat the nanoscale to create ultra-lightweight structureswith tailored properties.For example, researchers at the University of California, Berkeley, have developed a nano-engineered wing made of carbon nanotubes. This wing is incredibly lightweight, weighing only a few milligrams, yet it is also extremely strong and durable. The nanostructured design mimics the hierarchical structure of bird feathers, with nanoscale pores that reduce drag and enhance lift.Aerodynamic Performance and Flight Optimization.The aerodynamic performance of nano-engineered wings is a crucial factor in achieving efficient flight. Scientists are employing computational modeling and wind tunneltesting to optimize wing shapes and surfaces for maximumlift and reduced drag. The nano-scale precision of these materials allows for the creation of intricate aerodynamic features, such as micro-grooves and micro-ridges, that enhance airflow and reduce turbulence.In addition, researchers are exploring the use ofactive materials, such as shape-memory polymers, to enablewings to adapt their shape in response to varying flight conditions. These smart materials can be programmed to adjust the wing's camber and twist, improving maneuverability and stability during different flight phases.Applications and Future Prospects.The potential applications of nano-engineered wings are vast. They could lead to the development of:Autonomous micro air vehicles (MAVs): Small, unmanned flying devices with enhanced flight performance for surveillance, reconnaissance, and inspection tasks.Bio-inspired drones: Drones with wings that mimic the aerodynamic and structural properties of birds, enabling long-range flight and enhanced agility.High-altitude wind turbines: Ultra-lightweight wind turbines with wings designed for maximum lift at high altitudes, generating clean and sustainable energy.Biomedical implants: Nano-engineered wings could be used to create miniature medical devices, such as implantable sensors and drug delivery systems, that can navigate through the body with precision.The development of nano-engineered wings is still in its early stages, but the potential for transformative applications across various industries is immense. By harnessing the power of nanotechnology and drawing inspiration from nature, scientists and engineers are pushing the boundaries of flight and opening up new frontiers in aerial technology.。
含过渡金属氮化物的纳米多层薄膜增韧的研究进展
(1. School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China; 2. Shanghai Tool Factory Co., Ltd., Shanghai 200093, China)
第3期
周 超,等:含过渡金属氮化物的纳米多层薄膜增韧的研究进展
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Keywords: nano-multilayer films; transition metal nitrides; toughening; super-hard
纳米多层薄膜是由两种或两种以上具有不同 成分或结构的材料在薄膜生长方向上以纳米量级 相互交替沉积而形成的多层结构薄膜[1-4],被作为结 构材料或功能材料在机械加工、航空航天、能源等 领域具有良好的发展前景。在由两层交替沉积形成 的纳米多层薄膜中,其中一层的厚度通常要超过另 一层,前者称为“主体层”,也称“模板层”,后者 称为“调制层”。每相邻的主体层和调制层厚度之 和称为调制周期,通常用Λ表示[5]。纳米多层薄膜的 结构和性能主要取决于主体层,但调制层也能通过 自身的结构改变对纳米多层薄膜产生较大的影响[6]。 近年来纳米多层薄膜的制备方法主要集中在物理 气相沉积(physical vapor deposition, PVD)技术和化 学气相沉积(chemical vapor deposition, CVD)技术上[7], 其研究进展主要表现在主体层和调制层组合的开 发和调制周期的改变等方面。
介孔羟基磷灰石纳米粒子的制备及作为蛋白类缓释药物载体的应用
介孔羟基磷灰石纳米粒子的制备及作为蛋白类缓释药物载体的应用何晓梅;古莉娜【摘要】Mesoporous hydroxyapatite (HA ) nanoparticles were synthesized via gas‐liquid chemical precipitation combining with hydrothermal method .And the structure ,morphology and pore size distribution of HA were observed and measured using the X‐ray powder diffraction (XRD ) , transmission electron microscopy (TEM ) , Brunauer‐Emmett‐Teller ( BET ) , Barret‐Joyner‐Halenda scheme ( BJH ) and Fourier transform infrared spectrophotometer (FT‐IR) .The adsorption isoth erms of bovine serum albumin (BSA) on as‐prepared HA at various temperatures were obtained and the corresponding equilibrium data fitted better the Langmuir model better .Meanwhile ,the BSA cumulative release rate of the BSA‐loaded HA was investigated .The release rate was different at different pH values due to the effect of charge repulsion .Furthermore ,the vitro release was in accordance with the Korsmeyer‐Peppas equation and the release mechanism fitted the non‐Fickian diffusion .%利用气液沉淀和水热法相结合制备介孔羟基磷灰石(HA)纳米粒子,并采用X射线衍射(XRD)、透射电子显微镜(TEM)、比表面分析(BET)、孔径计算(BJH)、傅里叶红外(FT‐IR)对其进行表征。
利用脉冲激光沉积技术制备镍纳米颗粒及其生长过程中的应变场模拟
利用脉冲激光沉积技术制备镍纳米颗粒及其生长过程中的应变场模拟袁彩雷;张求龙;江子雄【摘要】利用脉冲激光沉积技术和快速退火成功地制备了镶嵌在非晶Al2O3薄膜中的Ni纳米颗粒,用高分辨率透射电子显微镜观察到镶嵌在非晶Al2O3薄膜中的Ni纳米颗粒,用有限元算法系统地模拟了Ni纳米颗粒生长过程中的应变场分布.研究发现:在Ni纳米颗粒的生长过程中,纳米颗粒受到母体A12O3材料的非均匀的偏应变的作用,而且随着Ni纳米颗粒的长大,纳米颗粒受到母体Al2O3材料的非均匀偏应变也逐渐增加.这种非均匀偏应变对于纳米颗粒的晶格结构和形貌有较大的影响,可以通过调节Ni纳米颗粒生长过程中的应变场来实现对Ni纳米颗粒界面态的调控,从而进一步优化Ni纳米颗粒的物理性能.%Ni nanoparticles embedded in the amorphous Al2O3 matrix were fabricated by using pulsed laser deposition and rapid thermal annealing. The results from high-resolution transmission electron microscope also revealed that the complete isolation of Ni nanoparticles embedded in amorphous A12O3 matrix. The growth strain of Ni nanoparticle embedded in the AI2O3 matrix was investigated. Finite element calculations clearly indicate that the Ni nanoparticle incurs a net deviatoric strain. With the growth of Ni nanoparticle, the larger Ni nanoparticles incur stronger net deviatoric strain, which will have much influence on the structure and morphology of Ni nanoparticles. Strain engineering is an effective tool for tailoring the properties of Ni nanoparticles.【期刊名称】《江西师范大学学报(自然科学版)》【年(卷),期】2012(036)002【总页数】5页(P111-115)【关键词】Ni纳米颗粒;应变场;脉冲激光沉积【作者】袁彩雷;张求龙;江子雄【作者单位】江西师范大学物理与通信电子学院,江西南昌330022;江西师范大学物理与通信电子学院,江西南昌330022;江西师范大学物理与通信电子学院,江西南昌330022【正文语种】中文【中图分类】O484.10 引言随着纳米颗粒尺寸的减小, 颗粒的表面积体积比急剧增大, 表面原子占粒子总原子数比例增大,因此表面态对纳米颗粒性能的影响非常显著[1-3]. 目前, 纳米材料的应用前景引起了科学工作者的高度关注, 已成为新世纪材料科学研究的热点, 并给传统材料产业带来了跨越式发展的重大机遇和挑战[4].近10年来, 由于磁性纳米颗粒具有非常广阔的应用前景, 对于纳米颗粒材料磁特性的研究已经引起了理论和实验学者的广泛关注[5-7]. 由于磁性纳米颗粒具有尺寸小、表面效应显著, 使其表现出许多不同于常规固体材料的新特性[8]. 金属纳米材料, 如具有铁磁性的金属Fe、Co、Ni等, 在磁流体、磁存储媒介、催化作用以及生物医学等科学领域有重要的应用,因而受到广泛的研究, 特别是Ni纳米颗粒, 在磁传感器、信息存储、生物分子分离等领域有着极其重要的应用[9-14]. 目前制备Ni纳米颗粒的方法有以下几种物理和化学方法: 高温分解法、阴极真空喷镀法、化学还原法、声化学沉积法等[15-21]. 近几年, 各种尺寸和形状的纳米颗粒的结构的制备及其特性的研究受到了科学工作者广泛的关注, 其中, 成功地制备各种尺寸和形状的纳米颗粒是一重大挑战[22]. 最近, 人们发现镶嵌在介电材料中的纳米颗粒, 在纳米颗粒的生长过程中总是不可避免地伴随着应变场的产生[23-25],这种应变场会对纳米颗粒的微观结构和形貌产生重要的影响, 进而影响纳米颗粒的物理和化学性能, 如光电磁学性能、催化性能等[26]. 研究工作还发现, 不同尺寸的纳米颗粒在其生长过程中, 受到应变场的分布有很大的不同, 这种应变场的不同对于纳米颗粒的微观结构和形貌都有较大的影响[27]. 但是到目前为止, 对磁性Ni纳米颗粒在其生长过程中的应变场分布还缺乏比较系统的研究. 因此, 成功制备镶嵌在介电母体材料中的Ni纳米颗粒, 并系统地认识Ni纳米颗粒在其生长过程中的应变场分布, 对于磁性Ni纳米材料的应用前景有非常重要的意义.1 实验利用脉冲激光沉积技术和快速退火制备镶嵌在非晶母体Al2O3中的磁性Ni纳米颗粒. 在制备过程中,准分子脉冲激光的波长为248 nm, 频率为5 Hz. 靶是由一个直径为25 mm的圆形的高纯度(质量分数为99.9%)的Al2O3靶材和一块长3 mm的方形Ni靶材组成, 保持Al2O3靶材和Ni靶材始终是物理性的粘结,而非化学性的粘结. 在沉积过程中, 利用一束准分子脉冲激光烧蚀固体靶, Al2O3和Ni组成的靶材缓慢地围绕中心轴旋转, 激光光束交替地烧蚀靶材的2种材料. P型(100)硅衬底先用SC1(NH4OH︰H2O2︰H2O=1︰1︰5)和SC2(HCl︰H2O2︰H2O=1︰1︰5)清洁, 然后浸入质量分数为1%的HF溶液以去除表面氧化层. 在整个沉积的过程中真空室的真空度为7×108 Torr,同时保持硅衬底的温度为室温. 沉积下来的样品在氮气中600 ℃快速退火120 s. 使用2010JEOL高分辨透射电子显微镜(HRTEM)观察这些样品的微观结构.图1(a)为经脉冲激光沉积技术生长样品的高分辨率透射电子显微镜图像, 显然图中没有任何纳米颗粒, 这是因为Ni都以单个的原子散布在Al2O3薄膜母体中, 也就是说Ni原子在低温下并没有成核.然后将这些样品在600 ℃快速退火120 s. 图1(b)为经过600 ℃快速退火样品的高分辨透射电子显微镜图像. 由图1(b)可以看出, 在Al2O3薄膜中, 有许多Ni纳米颗粒, 大部分颗粒都是成核的单晶纳米颗粒.图1(c)为单个的Ni纳米颗粒. 从图1可以发现, 经过在氮气中600 ℃快速退火后形成了镶嵌在Al2O3薄膜中的立方形状的单晶的Ni纳米颗粒. 这是因为, 随着温度的升高, Ni原子形成核的几率也提高, 纳米粒子的密度也会变大; 只要表面能足够, 会形成一些Ni核,而在其周围的Ni原子会通过表面扩散依附到已形成的Ni核上, 团聚成一个更大的Ni纳米颗粒[28].图1 样品的显微镜图像2 模拟与计算Ni纳米颗粒镶嵌在母体材料中产生应变的模型基于以下假设: 一个方形的各向同性的线弹性的纳米晶置于一个无限大各向同性的线弹性的母体材料中, 其中纳米晶是镶嵌在母体材料中的. 假设纳米晶被放在母体材料的一个非常小的空腔中, 由于周围母体材料的原子不能迅速移动以适应纳米晶在生长过程中的体积变化, 因而导致了纳米晶受到了周围母体材料的压缩应变. 用有限元算法(ANSYS软件)系统地模拟了镶嵌在Al2O3母体中的Ni纳米颗粒生长过程中的应变场强度的分布[29-31].在模拟中, Ni和Al2O3的杨氏模量分别为207、360 GPa, 泊松比分别为0.291、0.24. 假定Ni纳米晶的热膨胀系数为1%, 但事实上, 由于纳米晶生长导致初始应变可能远比1%的热膨胀系数大. 在有限元计算中, 假设方形的Ni纳米晶的位置在Al2O3母体的中心, Ni纳米晶和Al2O3母体的交界处是镶嵌的, 考虑Al2O3母体是无限大的和边界固定的.图2是尺寸为5、10、15 nm的Ni纳米颗粒镶嵌在Al2O3薄膜中的X-Y剖面的应力场分布图, 图3是尺寸为5、10、15 nm的Ni纳米晶的X-Y剖面的应变强度图, 图4是5、10、15 nm的Ni纳米晶在Y=0上沿X方向上的应变强度曲线. 显然Ni纳米颗粒受到周围Al2O3母体材料的压缩应变. 随着Ni纳米颗粒的长大, 它所受的周围母体材料的压缩应变强度增强. 对于大尺寸的Ni纳米颗粒, 其表面原子所受的母体材料的压缩应变比中心原子受到的压缩应变更强. 5 nm的Ni纳米颗粒的中心原子受到的应变和表面原子受到的应变几乎相同, 中心原子受到的应变和表面原子受到的应变强度均约为0.1. 这是因为尺寸较小的Ni纳米颗粒具有更大的表面积体积比, 纳米颗粒的表面原子数占纳米颗粒总原子数的比例很大, Ni纳米颗粒受到母体材料的压缩应变被分散到占纳米颗粒总原子数比例很大的表面连续原子上, 因此, 纳米颗粒受到的应变场分布比较均匀. 然而当Ni纳米颗粒生长到10和15 nm时, Ni纳米颗粒表面原子受到的应变明显强于中心原子受到的应变. 另外在Ni 纳米颗粒的棱角处原子受到的应变更大. 当Ni纳米颗粒的尺寸为10 nm时, 纳米颗粒表面原子受到的应变强度为0.229, 中心原子受到的应变强度为0.198, 棱角处原子受到的应变强度为0.283, 中心原子受到的应变比表面原子受到的应变减少了13.5%. 当Ni纳米颗粒的尺寸为15 nm时,纳米颗粒表面原子受到的应变强度为0.375, 中心原子受到的应变强度为0.320, 棱角处原子受到的应变强度为0.469, 中心原子受到的应变比表面原子受到的应变减少了14.9%. 对于尺寸较大的Ni纳米颗粒,表面积体积比比较小, 纳米颗粒的表面原子数占纳米颗粒总原子数的比例较少, Ni纳米颗粒应变被分散在占纳米颗粒总原子数比例较少的表面连续原子上, 因而导致Ni纳米颗粒表面原子受到的应变比中心原子受到的应变强. 因此, 在Ni纳米颗粒的生长过程中, 纳米颗粒受到母体Al2O3材料的非均匀的偏应变的作用, 而且随着Ni纳米颗粒的长大, 纳米颗粒受到母体Al2O3材料的非均匀偏应变也逐渐增加.这种存在的非均匀偏应变对于纳米颗粒的晶格结构和形貌有较大的影响, 从而极大地影响其物理性能[32].图2 直径为5、10、15 nm的Ni纳米晶的X-Y剖面的应变场分布图3 分别为5 nm(a)、10 nm(b)、15 nm(c)Ni纳米晶的X-Y剖面的应变强度图图4 分别为5、10、15 nm Ni纳米晶在Y=0上沿X方向上的应变强度曲线图3 结论用脉冲激光沉积和快速退火技术成功制备了镶嵌在Al2O3薄膜上的Ni纳米颗粒. 用高分辨透射电子显微镜观察发现这些Ni纳米晶具有面心立方的晶格结构. 用有限元算法研究Ni纳米晶在生长过程中的应变场分布, 发现在Ni纳米颗粒的生长过程中,纳米颗粒受到母体Al2O3材料的非均匀的偏应变的作用, 而且随着Ni纳米颗粒的长大, 纳米颗粒受到母体Al2O3材料的非均匀偏应变也逐渐增加. 这种存在的非均匀偏应变对于纳米颗粒的晶格结构和形貌有较大的影响. 因此, 系统地研究磁性Ni 纳米材料的应变场分布, 对有效地调控其物理化学性能有着非常重大的意义.4 参考文献【相关文献】[1] Fujii M, Inoue Y, Hayashi S, et al. 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Cite this:mun .,2011,47,3619–3621Fabrication of nanostructured metal nitrides with tailored composition and morphology wWei Li,ab Chang-Yan Cao,a Chao-Qiu Chen,ab Yong Zhao,a Wei-Guo Song*a and Lei Jiang*aReceived 10th December 2010,Accepted 17th January 2011DOI:10.1039/c0cc05485bUnprecedented multi-channel TiN micro/nanotubes as well as various metal nitride nanofibers,including TiN,VN,NbN and ternary metal nitride nanofibers,were fabricated by a template free electrospinning method combined with post-nitridation.Transition metal nitrides have desired properties for applications in supercapacitors,catalysis,hydrogen storage,optoelectronic devices,wear-resistant coating,etc.1–4For example,TiN is known for its hardness,corrosion and wear resistance,stability against oxidation,and high electrical conductivity,which makes it suitable as a protective coating material,anode materials for organic light-emitting diode and electrochemical capacitors in corrosive electrolytes.5,6Conventional fabrication methods for metal nitrides include metathesis reaction,5,7chemical vapor deposition,8molecular beam epitaxy,9carbothermal reduction/nitridation of oxides,10and ammonolysis of molecular precursors.11These methods have various drawbacks such as complicated procedures,low yields,and the use of corrosive and toxic chemicals (e.g.azide compounds).More importantly,the morphologies of metal nitrides by these methods are usually aggregated nanoparticles or thin films.There have been very few attempts to prepare hierarchically nanostructured metal nitrides.12However,for many surface applications such as catalysis,supercapacitor electrode or hydrogen storage,controlling the morphologies and porosity of nanostructured metal nitrides is crucial for better performances of these materials.Thus in terms of morphology control,it will be a breakthrough to synthesize one-dimensional (1D)metal nitrides,including nanofibers and micro/nanotubes in a facile,economical and controlled way.Electrospinning is a versatile and scalable technique to fabricate uniform and continuous one-dimensional nano-materials,mostly polymer,metal and metal oxide nanofibers.13–15So far only a few reports have been focused on the preparationof metal nitride nanowires,16,17but none have succeeded in fabricating multi-channel metal nitride micro/nanotubes.In this study,we developed an electrospinning method combined with a post-nitridation treatment to fabricate metal nitrides 1D materials at a large scale.In a typical experiment,about 0.5g nanofibers can be produced.This is a versatile method.And neither catalyst nor structural template is needed.A series of metal nitrides,including TiN,VN,NbN nanofibers,and ternary metal nitride nanofibers,with controlled metal ratios are prepared.In particular,unprecedented multi-channel TiN micro/nanotubes are produced.The number of channels can be readily controlled from one to three with specially designed electrospinning units,and the number of channels is directly associated with the surface areas of the samples.The general synthetic route of metal nitrides nanofibers or micro/nanotubes consists of two steps:(1)the electrospinning of the composite precursors with the desired morphologies;(2)direct nitridation of the precursors in an ammonia atmosphere to remove organic components and to convert metal species into metal nitrides,while the original morphologies of the precursors were retained.The detailed preparation procedure for each metal nitride is listed in ESI.w With this two step procedure,we are able to produce a series of metal nitride nanofibers as well as ternary metal nitride nanofibers with desired compositions.Fig.1a shows the SEM image of Ti(OBu)4/PVP composite nanofibers as the precursor for TiN nanofibers.The continuous nanofibers have a smooth surface with an average diameter of about 120nm.After direct nitridation at 9001C,the morpho-logy of as-synthesized TiN products remains as continuous and uniform nanofibers (Fig.1b and inset).TEM image (Fig.1c)also indicates that the diameter of TiN nanofibers is reduced to 40–60nm,probably due to the loss of PVP component and the crystallization of TiN,which has significantly higher bulk density than that of the precursor.And the surface of the TiN nanofibers appears to be relatively rough,since they are composed of TiN crystalline nanoparticles with a diameter of about 16nm (inset of Fig.1c).Fig.1d shows the high-resolution TEM image and the selected-area electron diffraction (SAED)pattern of TiN nanocrystalline grains.A lattice spacing of 0.242nm corresponds to the (111)plane of TiN.The SAED pattern demonstrates that the as-prepared TiN nanofibers are polycrystalline and the observed diffraction rings agree well with the expected lattice spacing of the osbornite TiN crystals.aBeijing National Laboratory for Molecular Sciences (BNLMS)&Key Laboratory for Molecular Nanostructures and Nanotechnology,Institute of Chemistry,Chinese Academy of Sciences,Beijing,100190,P.R.China.E-mail:wsong@;Fax:+8610-62557908;Tel:+8610-62557908bGraduate University of Chinese Academy of Sciences,Beijing,100049,P.R.Chinaw Electronic supplementary information (ESI)available:Experimental details and additional characterization of all metal nitrides.See DOI:10.1039/c0cc05485bChemCommDynamic Article Links/chemcommCOMMUNICATIOND o w n l o a d e d b y M a x P l a n c k I n s t i t u t f u r K o l l o i d o n 13 M a y 2011P u b l i s h e d o n 03 F e b r u a r y 2011 o n h t t p ://p u b s .r s c .o r g | d o i :10.1039/C 0C C 05485BView OnlineTemperature-dependent XRD pattern (Fig.S1,ESI w )analyses further confirm that the as-obtained nanofibers are TiN nano-fibers with osbornite crystalline phase of cubic TiN (JCPDS Card No.38-1420)after being treated in an ammonia atmosphere at 8001C or above.The average crystalline size of a TiN nano-fiber synthesized at 9001C is calculated by the Debye–Scherrer equation to be around 17nm,which is consistent with the TEM result (inset of Fig.1c).XPS and EDX analyses (Fig.S2,ESI w )indicate that small amounts of carbonaceous residuals are present in TiN nanofibers even after 10001C treatment.They may arise from the incomplete decomposition of the PVP matrix and such carbon residuals are common impurities in metal nitrides,2,16,18,19including the commercial TiN sample.This method can be extended to produce a variety of metal nitride materials with tailored compositions.1D vanadium nitride,niobium nitride and zirconium oxynitride continuous nanofibers have been successfully synthesized.Their TEM images,SEM images,XRD patterns and nitrogen adsorption–desorption isotherms are shown in ESI w (Fig.S3–S6).The lattice fringes observed in HRTEM images and SAED patterns (Fig.S6,ESI w )confirmed their crystallinity;and the XRD patterns of VN and NbN nanofibers could be readily indexed to cubic crystalline VN (Fm 3m [225],JCPDS Card No.65-7236)and NbN (P 63/mmc [194],JCPDS Card No.20-0801),con-firming their highly crystalline nature.It was slightly different for zirconium,though.Its XRD pattern indicated that the composition of as-prepared zirconium oxynitride nanofibers at 10001C was actually Zr 7O 8N 4(JCPDS Card No.50-1172).Besides simple metal nitrides,ternary metal nitride nanofibers can also be produced using this versatile method.Titaniumvanadium nitride (TiVN)nanofibers with a controllable metal composition were successfully prepared (SEM images in Fig.S7,ESI w ).As revealed in Fig.2,TiVN-0.5,TiVN-1.0and TiVN-1.5(numbers denote the Ti/V atomic ratio)nano-fibers exhibit XRD patterns that are similar to TiN and VN.However,with increasing titanium content in the TiVN nanofibers,the XRD peaks shift to lower angles,i.e.from the pattern of pure VN toward the pattern of pure TiN,proving the formation of a homogeneous Ti-V-N solid solution.7Both the EDX spectra (Fig.S8,ESI w )and results of ICP-AES analysis can confirm the Ti/V atomic ratio on these ternary samples.The diameter of electrospun nanofibers depends on many factors including the concentration of metal salts,humidity of the atmosphere,temperature etc.In addition,as shown in Fig.1and figures in ESI w ,the diameters of the nanofibers are not uniform.Therefore precise control of the diameters of nanofibers is indeed difficult.Micro/nanotubes are superior materials for surface applications,as they provide inside and outside surfaces.The chemistry on the inside surface may be influenced by the confined space of the micro/nanotubes.Coaxial electrospinning has been a powerful tool for fabricating ultralong polymer and metal oxide micro/nanotubes.20–22Recently,Zhao et al.14,23,24reported a multifluidic electrospinning technique to prepare multi-channel titanium oxide microtubes.In this work,we exploited the technique to synthesize hierarchical TiN multi-channel micro/nanotubes,which have never been reported in the literature.As shown in Fig.3,TiN micro/nanotubes with one to three channels were successfully fabricated using the two step procedure developed in this study.This is the first report of such tubular metal nitride materials.The elaborate design of the spinneret is crucial in producing these novel TiN multi-channel tubes.By carefully adjusting the number of inner capillaries and their relative positions to the outer orifice,Fig.1(a)SEM image of typical electrospun Ti(OBu)4/PVP composite nanofibers as the precursor of TiN nanofibers (inset:SEM image with higher magnification);(b)SEM image of TiN nanofibers synthesized at 9001C (inset:SEM image with higher magnification);(c)TEM images of TiN nanofibers fabricated at 9001C (inset shows a single TiN nanofiber with higher magnification);and (d)high-resolution TEM image of an individual TiN nanofiber and the inset is its SAED pattern.Fig.2Part of the XRD pattern of ternary TiVN nanofibers synthesized at 9001C with increasing content of Ti.As a reference,the patterns of pure VN and TiN nanofibers synthesized at the same temperature are also shown.D o w n l o a d e d b y M a x P l a n c k I n s t i t u t f u r K o l l o i d o n 13 M a y 2011P u b l i s h e d o n 03 F e b r u a r y 2011 o n h t t p ://p u b s .r s c .o r g | d o i :10.1039/C 0C C 05485Bwe were able to produce multi-channel Ti(OBu)4/PVP precursor composite tubes (Fig.S9,ESI w ),which were then converted into TiN micro/nanotubes with desired channel numbers.Similar to what is observed on TiN nanofibers,the overall sizes of the multi-channel TiN tubes were all significantly smaller than those of the corresponding precursors.These multi-channel tubes with a rough surface were also composed of TiN crystalline grains.The walls of these tubes were rather solid.There were very few broken pieces,indicating that the nitridation process did not cause the collapse of the tubular structures.XRD patterns of these multi-channel TiN micro/nanotubes are illustrated in ESI w (Fig.S10),indicating the osbornite crystalline phase of cubic TiN.The surface characteristics of these as-prepared TiN samples were characterized by nitrogen adsorption–desorption isotherm measurements (shown in Fig.S11,ESI w ).Table 1summarizes their BET surface area.For a series of samples prepared at 8001C,the surface areas of the TiN samples directly rely on the number of channels.From TiN nanofibers (which may be considered as zero channel TiN tubes)to three channel tubes,the surface area of the micro/nanotubes increase roughly in a linear manner with the number.The multifluidic compound-jet electrospinning allows facile fabrication of metal nitride multi-channel micro/nanotubes.This method does not require any hard template,avoiding the compli-cated template removal process.These special TiN multi-channel micro/nanotubes can be produced at a large scale,as shown in more SEM images (Fig.S12,ESI w )with longer electrospinning time or using multiple electrospinning jets simultaneously.The production of this method is significantly higher than the reportedmethod by complicated anodization of a metallic Ti foil to produce TiN nanotubes.25In addition,only single channel tubes can be produce by the Ti foil anodization method.Compared to conventional TiN nanoparticles or microsphere structures,the non-woven mats with inter-connected nanofibers and nanotubes have larger surface-to-volume ratio,larger surface area,better mechanic stability and especially independently accessible channels.These are very desirable features for surface related applications.We envision interesting properties to be discovered in catalysis and electrochemical tests.In summary,we developed a versatile and controllable method to produce metal nitride 1D materials,including TiN,VN,NbN nanofibers as well as ternary metal nitride nanofibers with con-trolled metal ratios.Novel multi-channel TiN micro/nanotubes are produced with controlled number of channels.Study on the properties of these materials in catalysis is underway.We thank the financial supports from the National Natural Science Foundation of China (NSFC 50725207,20821003),National Basic Research Program of China (2007CB936400,2009CB930400)and the Chinese Academy of Sciences.Notes and references1D.Choi,G.E.Blomgren and P.N.Kumta,Adv.Mater.,2006,18,1178.2A.Fischer,P.Makowski,J.O.Mueller,M.Antonietti,A.Thomas and F.Goettmann,ChemSusChem ,2008,1,444.tella,B.Gan,K.Davies,D.McKenzie and D.McCulloch,Surf.Coat.Technol.,2006,200,3605.4B.Bogdanovic,M.Felderhoff,S.Kaskel, A.Pommerin,K.Schlichte and F.Schu th,Adv.Mater.,2003,15,1012.5R.A.Janes,M.Aldissi and R.B.Kaner,Chem.Mater.,2003,15,4431.6V.Adamovich,A.Shoustikov and M.Thompson,Adv.Mater.,1999,11,727.7A.Fischer,J.O.Mu ller,M.Antonietti and A.Thomas,ACS Nano ,2008,2,2489.8J.Dekker,P.Put,H.Veringa and J.Schoonman,J.Mater.Chem.,1994,4,689.9F.Werner,F.Limbach,M.Carsten,C.Denker,J.Malindretos and A.Rizzi,Nano Lett.,2009,9,1567.10H.Zhao,M.Lei,J.Jian and X.Chen,J.Am.Chem.Soc.,2005,127,15722.11S.Kaskel,K.Schlichte,G.Chaplais and M.Khanna,J.Mater.Chem.,2003,13,1496.12J.H.Bang 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images of hierarchical TiN micro/nanotubes with channel numbers from one to three,respectively;(e)–(g)corresponding TEM images of multi-channel TiN micro/nanotubes.All the tubes above are prepared at 10001C.Table 1Porous characteristics of TiN nanofibers and multi-channel micro/nanotubes Sample BET surface area/m 2g À1TiN nanofibers55.8TiN one-channel micro/nanotubes 70.1TiN two-channel micro/nanotubes 85.9TiNthree-channel mirco/nanotubes110.4D o w n l o a d e d b y M a x P l a n c k I n s t i t u t f u r K o l l o i d o n 13 M a y 2011P u b l i s h e d o n 03 F e b r u a r y 2011 o n h t t p ://p u b s .r s c .o r g | d o i :10.1039/C 0C C 05485B。