纳米材料-英文介绍PPT课件

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纳米科技全英文ppt

STM
the birth of cluster science and the invention of the scanning tunneling microscope (STM). This development led to the discovery of fullerenes in 1985 and carbon nanotubes a few years later. In another development, the synthesis and properties of semiconductor nanocrystals was studied; this led to a fast increasing number of metal and metal oxide nanoparticles and quantum dots. The atomic force microscope was invented six years after the STM was invented. In 2000, the United States National Nanotechnology Initiative was founded to coordinate Federal nanotechnology research and development and is evaluated by the President's Council of Advisors on Science and Technology.
The stone implements
The core plate
A brief introduction to the nanotechnology

纳米材料学英文教学PPT.ppt

2021/3/5
Co/Cu(111) H.C. Monoharan, C.P. Lutz, D.M. Eigler Nature 403 (2000) 512
• Association: the bias was raised to 500 mV for 10 s
• It is not possible to break the C-H and C-C bonds with a single electron process at this voltage, especially as their bond energies are about 2 and 3 times higher than the C-I bond.
Pried them apart into iodine and phenyl (C6H5) by injecting electrons from the STM tip (a).
Used the tip to pull the iodine away (b and c) and draw the phenyl molecules closer together (d).
MIX-AND-MATCH molecule: Atomic engineers eventually hope to create molecules from scratch, adding atoms exactly as needed to perform specific functions. This molecule, with 18 cesium and 18 iodine atoms, was built--one atom at a time--with a STM
2021/3/5

纳米材料基础(英文ppt)

ClassificationClassification is based on the number of dimensions, which are not confined to the nanoscale range (<100 nm).(1) zero-dimensional (0-D),(2) one-dimensional(1-D),(3) two-dimensional (2-D), and(4) three-dimensional (3-D).2One-dimensional nanomaterialsOne dimension that is outside the nanoscale.This leads to needle like-shaped nanomaterials.1-D materials include nanotubes, nanorods, andnanowires.1-D nanomaterials can beAmorphous or crystallineSingle crystalline or polycrystallineChemically pure or impureStandalone materials or embedded in within another medium Metallic, ceramic, or polymeric4Two-dimensional nanomaterials Two of the dimensions are not confined to the nanoscale.2-D nanomaterials exhibit plate-like shapes.Two-dimensional nanomaterials include nanofilms,nanolayers, and nanocoatings.2-D nanomaterials can be:Amorphous or crystallineMade up of various chemical compositionsUsed as a single layer or as multilayer structuresDeposited on a substrateIntegrated in a surrounding matrix materialMetallic, ceramic, or polymeric5Three Three--dimensional space showing the relationships among 0among 0--D, 1D, 1--D, 2D, 2--D, and D, and 33-D D nanomaterials nanomaterials nanomaterials..7Summaryof 2-D and3-Dcrystallinestructures 8Matrix-reinforced and layerednanocompositesThese materials are formed of two or more materials with very distinctive properties that act synergistically to create properties that cannot be achieved by each single material alone. The matrix of the nanocomposite, which can be polymeric, metallic, or ceramic, has dimensions larger than the nanoscale, whereas the reinforcing phase is 9commonly at the nanoscale.Carbon materials2s and 2p electrons available for bondingDiamond and graphite are twoallotropes of carbon:pure forms of the same element that differ in structure.11DIAMOND- chemical bonding is purely covalent - highly symmetrical unit cell - extremely hard - low electrical conductivity - high thermal conductivity (superior) - optically transparent - used as gemstones and industrial grinding, machining and cutting12GRAPHITE• Layered structure with strong bonding within the planar layers and weak, van der Waals bonding between layers • Easy interplanar cleavage, applications as a lubricant and for writing (pencils) • Good electrical conductor • Chemically stable even at high temperatures • excellent thermal shock resistanceApplications:Commonly used as heating elements (in non- oxidizing atmospheres), metallurgical crucibles, casting molds, electrical contacts, brushes and resisto1r3s, high temperature refractories, welding electrodes, air purification systems, etc.GraphiteGraphite is a layered compound. In each layer, the carbon atoms are arranged in a hexagonal lattice with separation of 0.142 nm, and thedistance between planes is 0.335 nmThe acoustic and thermal properties of graphite are highly anisotropic, since phonons propagate very quickly along the tightly-bound planes, but are slower to travel from one plane to another.14/wiki/GraphiteGrapheneGraphene is an one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. It can be viewed as an atomic-scale chicken wire made of carbon atoms and their bondsThe carbon-carbon bondlength in graphene is about0.142 nm. Graphene is thebasic structural element ofsome carbon allotropesincluding graphite, carbon15nanotubes and fullerenes.Allotropes of carbon3D 0D1D16a) diamond b) graphite c) lonsdaleite(hexagonal diamond) d) - f) fullerenes (C60, C540, C70); g) amorphous carbon h) carbon nanotube2D - ???Wikipedia17SCIENCE, June 2010If there's a rock star in the world of materials, it's graphene: single-atom–thick sheets of carbon prized forits off-the-charts ability to conduct electrons and for being all but transparent.Those qualities make graphene a tantalizing alternative for use as a transparent conductor, the sort now found in everything from computer displays and flat panel TVs to ATM touch screens and solar cells. But the material has been tough to manufacture in anything larger than flakes a few centimeters across. Now researchers have managed to create rectangular sheets of graphene 76 centimeters in the diagonal direction and even use them to create a working touchscreen display18Quantum effectsThe overall behavior of bulk crystalline materials changes when the dimensions are reduced to the nanoscale. For 0-D nanomaterials, where all the dimensions are at the nanoscale, an electron is confined in 3-D space. No electron delocalization (freedom to move) occurs. For 1-D nanomaterials, electron confinement occurs in 2-D, whereas delocalization takes place along the long axis of the nanowire/rod/tube. In the case of 2-D nanomaterials, the conduction electrons will be confined across the thickness but delocalized in the plane of the sheet.19Electrons confinementFor 0-D nanomaterials the electrons are fully confined. For 3-D nanomaterials the electrons are fully delocalized. In 1-D and 2-D nanomaterials, electron confinement and delocalization coexist. The effect of confinement on the resulting energy states can be calculated by quantum mechanics, as the “particle in the box” problem. An electron is considered to exist inside of an infinitely deep potential well (region of negative energies), from which it cannot escape and is confined by the dimensions of the nanostructure.20Energieswhere h¯ ≡ h/2π, h is Planck’s constant, m is the mass of the electron, L is the width (confinement) of the infinitely deep potential well, and nx, ny, and nz are the principal quantum numbers in the three dimensions x, y, and z.The smaller the dimensions of the nanostructure(smaller L), the wider is the separation between theenergy levels, leading to a spectrum of21discreet energies.What’s different at the nanoscale?Each of the different sized arrangement of gold atoms absorbs and reflects light differently based on its energylevels, which are determined by size and bonding arrangement. This is true for many materials when the particles have a size that is less than 100 nanometers in atleast one dimension.22Energy levels in infinite quantum well23The finite potential wellFor the finite potential well, the solution to the Schrodinger equation gives a wavefunction with an exponentially decaying penetration into the classically forbidden region.Confining a particle to a smaller space requires a larger confinement energy. Since the wavefunction penetration effectively "enlarges the box", the finite well energy levels are lower than thosefor the infinite well.The solution for -L/2 < x < L/2 and elsewhere must satisfy the equationWith the substitution24The finite potential well25Comparison of Infinite and Finite Potential WellsEigenstates with E < V0 are bound or localized.26Eigenstates with E > V0 are unbound or delocalizedElectron energy densityThe behavior of electrons in solids depends upon the distribution of energy among the electrons:This distribution determines the probability that a given energy state will be occupied, but must be multiplied by the density of states function to weight the probability by the number of states available at a given energy.Density of states in (a) metal, (b) semimetal (e.g.graphite).27。

纳米材料简介ppt课件

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2 在磁性材料中的应用纳米磁性材料包括纳米磁粉材料、纳米磁膜材料和纳米磁性液体。
在铁磁质纳米磁性材料中，存在磁单畴结构，具有超顺磁性，即纳米结构的尺寸小于磁单畴的临界尺寸时，纳米结构中的原子磁矩有序化，具有顺磁质的特性，而在无外场时，对任何一个方向都不显磁性。加外磁场后，形成磁矩有序化，形成过程不是瞬时的，而有一个驰豫时间。超顺磁性材料，矫顽力远比普通材料大，对高密度磁记录元件十分重要。 3 在催化剂领域应用
纳米粒子表面积大、表面活性中心多，为催化剂提供了必要条件。目前纳米粉材如铂黑、银、氧化铝和氧化铁等广泛用于高分子聚合物氧化、还原及合成反应的催化剂。如用纳米镍粉作为火箭固体燃料反应催化剂，燃烧效率提高100倍；以粒度小于100nm的镍和铜锌合金的纳米材料为主要成分制成加氢催化剂，可使有机物的氢化率达到传统镍催化剂的10倍；用纳米TiO2制成光催化剂具有很强的氧化还原能力，可分解废水中的卤代烃、有机酸、酚、硝基芳烃、取代苯胺及空气中的甲醇、甲醛、丙酮等污染物。
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CONTENTS
1
什么是纳米
2
什么是纳米材料
3 纳米材料的纳米效应
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纳米材料的分类
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纳米材料的应用
6 纳米材料与未来社会
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1 什么是纳米
纳米（nanometer）：长度单位，即10-9m。纳米有多大？
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2 什么是纳米材料
纳米级结构材料简称为纳米材料(nanometer material)，是指其结构单元的尺寸介于1纳米～100纳米范围之间。由于它的尺寸已经接近电子的相干长度，它的性质因为强相干所带来的自组织使得性质发生很大变化。并且，其尺度已接近光的波长，加上其具有大表面的特殊效应，因此其所表现的特性，例如熔点、磁性、光学、导热、导电特性等等，往往不同于该物质在整体状态时所表现的性质。纳米颗粒材料又称为超微颗粒材料，由纳米粒子(nano particle)组成。纳米粒子也叫超微颗粒，一般是指尺寸在1～100nm间的粒子，是处在原子簇和宏观物体交界的过渡区域，从通常的关于微观和宏观的观点看，这样的系统既非典型的微观系统亦非典型的宏观系统，是一种典型的介观系统，它具有表面效应、小尺寸效应和宏观量子隧道效应。当人们将宏观物体细分成超微颗粒（纳米级）后，它将显示出许多奇异的特性，即它的稀土纳米材料光学、热学、电学、磁学、力学以及化学方面的性质和大块固体时相比将会有显著的不同。

纳米医用材料PPT课件

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目前，国际上纳米生物技术在医药领域的研究已取得一定的进展。美国、日本、德国等国家均已将纳米生物技术作为21世纪的科研优先项目予以重点发展。
纳米材料定义
– 纳米材料是指在三维空间中至少有一维处于纳米尺度范围(1-100nm)或由它们作为基本单元构成的材料，这大约相当于10~100个原子紧密排列在一起的尺度。
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纳米在生物、医学中的应用更是使得现代医学有了较大的发展Байду номын сангаас间，使人们在对生命探索、治疗疾病、卫生保健等方面有了进一步的发展。国际社会纳米生物技术的研究范围注意涉及纳米生物材料、药物和基因运转纳米载体、纳米生物相容性人工器官、纳米生物传感器和成像技术，以及利用扫描探针显微镜分析蛋白质和DNA的结构与功能等重要领域。
纳米医用材料
纳米的概念
纳米(nanometer) 纳米是一个长度计量单位，1纳米 = 10-9米。人的一根头发丝的直径相当于6万个纳米。
人高
针头红血球冠状病毒 DNA分子氢原子
100万纳米 20亿纳米
1000纳米
100纳米
1纳米
0.1纳米
Introduction • 纳米一词源出于希腊，意指“侏儒”，现作为微观世界里的长度单位，一纳米等大约是三、四个碳原子的宽度。 • 美国物理学家、两次诺贝尔奖得主费恩曼教授（R. Feynman）早在1950年代末就指出，人类若能控制物体微小规模上的排序，将可获得许多具有特殊性能的物质，这是对纳米技术最早的构想。 • 纳米技术一词则始见于1974年，出自科学家谷口纪南（Norio Taniguchi）对精密机械加工的描述。
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纳米生物医学材料的分类
• 生物活性材料

纳米技术_英语ppt

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Structural constituent units （组织机构单位）——Nanorobots （纳米机器人)
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the connection of nure formed of numerous nanorobots 无数的纳米机器人形成的基本的纤维结构
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Summary
•The many nanotechnology in theory, not yet applied to the actual. 很多的纳米技术处于理论、实验室阶段尚不能应用于实际 •Nanotechnology may bring environmental pollution. 纳米技术可能会带来环境污染 •Nanotechnology will bring huge changes to our life. 纳米技术将会给我们的生活带来巨大的变革
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Control center——Nanomachines (纳米计算机）
Nanotechnology applications developed computer memory chips, and its volume are only a few hundred atoms in size, it is not only almost do not need to spend any energy, and its performance than today's computers many times more powerful. U.S. connecting nanotubes are developing a method of the nanotubes connected using this method can be used as a chip component, play electronic switch, amplification, and the function of the transistor.

纳米材料PPT课件

从1999年开始，美国政府决定把纳米科技研究列入21世纪十一个关键领域之一。
2.日本：
日本政府宣布，将纳米技术列为新五年科技基本计划的研发重点，并实行“管产学”联合攻关，加速这一高新技术的开发。
博士论文答辩
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3.德国：
德国政府宣布，将纳米技术列为新五年科技基本计划的研发重点，并实行“管产学”联合攻关，加速这一高新技术的开发。
零维纳米材料一维纳米材料
二维纳米材料
三维纳米材料
纳米操纵纳米加工纳米光刻
博士论文答辩
纳米压痕
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纳米材料学（Nanomaterials）：
研究纳米材料的设计、制备、性能和应用的一门纳米应用科学。
尺寸大小：
（1）影响物质中电子的波动性；原子的相互作用
（2）不改变化学成分，可以调节尺寸控制材料
肉眼观察的范围
介观领域
肉眼可见最小物体为下限-------无限大的宇宙天体的宏观领域
微观领域
（Microcosmic Domain）
分子、原子为最大起点------无限的微观领域
博士论文答辩
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介观领域的奇异：
100nm
1nm
纳米是一个长度单位
Nano
Size
Nano:
量子效应、物质的局限性、巨大的表面及界面效应
美国IBM公司的首席科学家阿姆斯壮预言：
“正像20世纪70年代微电子技术产生信息革命一样，纳米科学技术将成为21世纪信息时代的核心！”
博士论文答辩
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二.纳米科技的研究内容：
纳米究竟有多大？ 1 nm = 10-9 m
1 nm 相当于10个氢原子紧密地排列在一起所具有的长度！

神奇的纳米材料PPT课件

科学新视野
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5/23/2020
• 2001年当时美国总统Clinton建立了 National Nanotechnology Initiative ( NNI) ，以推动和协调美国的纳米研究。
The covers of the reports from the National
Nanotechnology Advisory Panel to US President.
科学新视野
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3. 观察纳米世界的主要工具
• 扫描隧道显微镜（STM） • 原子力显微镜（AFM） • 扫描电子显微镜（SEM） • 透射电子显微镜（TEM）
科学新视野
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5/23/2020
3.1 扫描隧道显微镜(STM)
扫描隧道显微镜的照片
刻蚀的钨针尖
科学新视野 5/23/2020
科学新视野
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• 1990年首届国际纳米技术科技会议在美国巴尔的摩（Baltimore）举办
科学新视野
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科学新视野 5/23/2020
一道习题
Klever = 2 nN/nm Ksilicon = ∞ KZnO = ? 如果纳米线长1um，直径100nm，请计算纳米线的弹性模量E。
碳纳米管，各种纳米线
薄膜
科学新视野
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科学新视野
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2. 纳米的起源和发展Fra bibliotek• 1959年美国物理学家费曼（Richard Feynman）首先提出，组装原子或分子是可能的。
科学新视野

英文-无机纳米材料光解水ppt课件

▪ Semiconductors with smaller bandgaps can be used, can absorb a greater fraction of the solar spectrum
Photoelectrochemical devices
Photoelectrochemical devices
▪ in 1971 by Fujishima and Honda
▪ suspended semiconductor particles:
▪ Bard demonstrated the photocatalytic effects
▪ photochemical diodes:
▪ Arthur Nozik formulated the concept
2 Brief history of nanoscale photoelectrochemistry and photocatalysis
▪ Modern nanoscience:
▪ only about 40 years old, began in 1974 with Dingle’s discovery of quantum size effects in thin films
英文无机纳米材料光解水ppt课件
Inorganic nanostructures for photoelectrochemical and photocatalytic
water splitting
Frank E. Osterloh
University of California, Davis Department of Chemistry
▪ Efficiencies between 12.4% and over 18% have been achieved, i.e. about half of the theoretical efficiency limit for these devices.