Nanometer is the unit of length, and the symbol is nm. 1nm =1nm = 10 angstrom (billionth of a meter), which is about the length of10 atoms. Suppose that a hair has a diameter of 0.05 mm and is divided into 50,000 hairs on average in the radial direction, and the thickness of each hair is about 1nm.
The significance of nanotechnology-1
The so-called nanotechnology refers to a brand-new technology to study the motion laws and characteristics of electrons, atoms and molecules in the scale of 0. 1~ 100 nanometers. In the process of studying the composition of matter, scientists found that several or dozens of countable atoms or molecules isolated on the nanometer scale show many new characteristics, and the technology of manufacturing equipment with specific functions by using these characteristics is called nanotechnology.
The main differences between nanotechnology and microelectronics are: nanotechnology studies the realization of specific functions of equipment by controlling single atoms and molecules, and it works by using the fluctuation of electrons; Microelectronics technology mainly realizes its function by controlling the population of electrons and works by using the particle nature of electrons. The purpose of people's research and development of nanotechnology is to achieve effective control of the entire micro-world.
Nanotechnology is a comprehensive subject with strong cross-cutting, and its research content involves the vast field of modern science and technology. From 65438 to 0993, the International Steering Committee of Nanotechnology divided nanotechnology into six sub-disciplines: nanoelectronics, nanophysics, nanochemistry, nanobiology, nanofabrication and nanometrology. Among them, nano-physics and nano-chemistry are the theoretical basis of nano-technology, and nano-electronics is the most important content of nano-technology.
The significance of nanotechnology -2
Nanotechnology (nanotechnology)
Nano-technology is actually a technology to make substances with a single atom and molecule.
Judging from the research so far, there are three concepts about nanotechnology. The first is 1986, the molecular nanotechnology put forward by American scientist Dr. drexler in his book The Machine of Creation. According to this concept, we can make the machine of combining molecules practical, so that we can combine various molecules at will and make any molecular structure. The nanotechnology of this concept has not made significant progress.
The second concept defines nanotechnology as the limit of micromachining technology. That is, the technology of artificially forming nano-scale structures through nano-precision "processing". This nano-scale processing technology also makes the miniaturization of semiconductors reach the limit. Even if the existing technology continues to develop, it will eventually reach the limit in theory. This is because if the line width of the circuit is reduced, the insulation film forming the circuit will be extremely thin, which will destroy the insulation effect. In addition, there are problems such as fever and trembling. In order to solve these problems, researchers are studying new nanotechnology.
The third concept is put forward from a biological point of view. It turns out that organisms have nano-scale structures in cells and biomembranes.
The so-called nanotechnology refers to a brand-new technology to study the motion laws and characteristics of electrons, atoms and molecules in the scale of 0. 1~ 100 nanometers. In the process of studying the composition of matter, scientists found that several or dozens of countable atoms or molecules isolated on the nanometer scale show many new characteristics, and the technology of manufacturing equipment with specific functions by using these characteristics is called nanotechnology.
Nanotechnology is a comprehensive subject with strong cross-cutting, and its research content involves the vast field of modern science and technology.
Nanotechnology now includes nano-biology, nano-electronics, nano-materials, nano-mechanics, nano-chemistry and other disciplines. From micro-technology including microelectronics to nano-technology, people's understanding of the micro-world is getting deeper and deeper, and people's understanding and transformation level of the micro-world has reached an unprecedented height. Qian Xuesen, a famous scientist in China, also pointed out that the structure around nanometer and below nanometer is a key point in the next stage of scientific and technological development, which will be a technological revolution, thus causing another industrial revolution in 2 1 century.
Although there is still a long way to go before the application stage, developed countries such as the United States, Japan and Britain attach great importance to nanotechnology because of its extremely broad application prospects, and have made research plans and carried out related research.
Characteristics of nano-electronic devices
The performance of electronic devices manufactured by nanotechnology is much better than that of traditional electronic devices.
The working speed is fast, and the working speed of nano-electronic devices is 1000 times that of silicon devices, so the product performance can be greatly improved. Low power consumption, the power consumption of nano-electronic devices is only 1/ ... > silicon devices; & gt
Question 2: What is nanotechnology? For some time, nanotechnology has appeared frequently in the media, and the advantages of nanotechnology, nanomaterials and products manufactured by nanotechnology have also been widely publicized. So, what is nanotechnology? This paper introduces this knowledge for beginners' reference.
. Nanometer is the unit of length, and the symbol is nm. 1nm =1nm = 10 m (billionth of a meter), which is about the length of10 atoms. Suppose that a hair has a diameter of 0.05 mm and is divided into 50,000 hairs on average in the radial direction, and the thickness of each hair is about 1nm.
. 1, the meaning of nanotechnology
The so-called nanotechnology refers to a brand-new technology to study the motion laws and characteristics of electrons, atoms and molecules in the scale of 0. 1~ 100 nanometers. In the process of studying the composition of matter, scientists found that several or dozens of countable atoms or molecules isolated on the nanometer scale show many new characteristics, and the technology of manufacturing equipment with specific functions by using these characteristics is called nanotechnology.
The main differences between nanotechnology and microelectronics are: nanotechnology studies the realization of specific functions of equipment by controlling single atoms and molecules, and it works by using the fluctuation of electrons; Microelectronics technology mainly realizes its function by controlling the population of electrons and works by using the particle nature of electrons. The purpose of people's research and development of nanotechnology is to achieve effective control of the entire micro-world.
Nanotechnology is a comprehensive subject with strong cross-cutting, and its research content involves the vast field of modern science and technology. From 65438 to 0993, the International Steering Committee of Nanotechnology divided nanotechnology into six sub-disciplines: nanoelectronics, nanophysics, nanochemistry, nanobiology, nanofabrication and nanometrology. Among them, nano-physics and nano-chemistry are the theoretical basis of nano-technology, and nano-electronics is the most important content of nano-technology.
.2, the characteristics of nano-electronic devices
The performance of electronic devices manufactured by nanotechnology is much better than that of traditional electronic devices.
The working speed is fast, and the working speed of nano-electronic devices is 1000 times that of silicon devices, so the product performance can be greatly improved. Low power consumption, the power consumption of nano-electronic devices is only11000 of that of silicon devices. There is a lot of information storage. On a 5-inch CD less than the size of the palm of your hand, you can store all the books of at least 30 Beijing libraries. Small size and light weight can greatly reduce the size and weight of various electronic products.
Question 3: What nano-materials are there? It can be roughly divided into four categories: nano-powder, nano-fiber, nano-film and nano-block. Among them, nano-powder has the longest development time and the most mature technology, which is the basis for the production of other three types of products.
Nanometer powder
Also known as ultrafine powder or ultrafine powder, it generally refers to powder or particles with a particle size below 100 nm, which is a solid particulate matter in an intermediate state between atoms, molecules and macroscopic objects. Can be used for: high-density magnetic recording materials; Absorb stealth materials; Magnetic fluid material; Radiation protection materials; Monocrystalline silicon and polishing materials for precision optical devices: microchip heat-conducting substrate and wiring materials; Microelectronic packaging materials; Photoelectric materials; Advanced battery electrode materials: solar battery materials; Efficient catalyst; Efficient combustion improver; Sensitive element; High toughness ceramic materials (ceramics that are not easy to break, used in ceramic engines, etc. ); Human body repair materials; Anticancer preparations, etc.
Nanofibers are linear materials with nanometer diameter and long length. Can be used for: microfilament, microfiber (an important part of quantum computer and photonic computer in the future) materials; New laser or LED materials, etc.
Nanometer thin film
Nano-membranes are divided into granular membranes and dense membranes. Particle film is a thin film with nano-particles stuck together, with a very fine gap in the middle. Dense film refers to the thin film with dense film layer but nanometer grain size. Can be used for: gas catalysis (such as automobile exhaust treatment) materials; Filter material; High density magnetic recording materials; Photosensitive material; Flat panel display materials; Superconducting materials, etc.
Nano-block: it is a nano-particle material obtained by high-pressure molding of nano-powder or controlling the crystallization of metal liquid. The main uses are: ultra-high strength materials; Intelligent metal materials, etc.
Question 4: What exactly are nanomaterials? What exactly are nanomaterials? Date of publication: May, 2008-1615:14 Number of visitors: 227 The Ministry of Health, Labour and Welfare of Japan held the second joint seminar on the safety of nanomaterials on April 4, 2008 (the meeting was chaired by Akiji Fukushima, director of Japan Biometrics Research Center of the Central Labor Disaster Prevention Association. This time, * * held two seminars, "Preventing workers from contacting chemicals whose harm to human body is unclear" and "Safety of nano-materials". The theme this time is "What is nanomaterial?" . In addition, the basic data such as the use and output of nano-materials were published, and the status report was made, confirming the basic data to be discussed in future seminars. Regarding the "scope of nano-materials", the person in charge of the Japanese Ministry of Health, Labor and Welfare said that according to the scheme of TC229 Committee of ISO (International Standardization Committee), it is generally defined as "materials with one-dimensional size less than 100nm". In addition, it is said that the relevant administrative departments of the United States, Britain, Australia and other countries have basically adopted this definition. It also points out how to define nano-materials when they gather together to reach micron size. Fullerene Engineering Group of Nanomaterials Laboratory of Materials and Materials Research Institute explains "Properties of Nanomaterials". The team pointed out that nano-materials will be abnormal when their electronic state changes, and their chemical, mechanical and electrical properties will be abnormal. For example, the calculated surface area of single-layer carbon nanotubes is about 1300m2/g, and that of multi-layer carbon nanotubes is about 20 ~ 180m2/g, which is quite different. Electronically, the particle size of semiconductor nanoparticles turns red at 4.5nm, green at 3.5nm and blue at 2.5nm, which are unimaginable "nano-size effects" of ordinary materials. The amount of carbon black used in tires is mostly about the use and output of nano-materials. Toray Management Research Institute (Pu 'an City, Chiba Prefecture), which conducted a survey in Ping 19 (2007), announced the survey results. The order of main nano-materials is: carbon black (carbon) 830000t, silica 13500t, titanium oxide 1250t, zinc oxide 480t .. In nanotechnology, nano-carbon fibers are 60-70t, multi-layer carbon nanotubes are 60t, fullerenes are 2t, and single-layer carbon nanotubes are 0./kloc-0. Among them, carbon black accounts for about 97.8%, which is mainly used for tires. The main use of silicon dioxide is silicone rubber, accounting for 57%. 60% of titanium oxide is used in cosmetics. The Nanotechnology Industry Promotion Association (NBCI) established by Japan's Ministry of Economy, Trade and Industry introduced the "development status of nanomaterials". Fullerene has been used in sporting goods, and the current research and development projects are developing its applications in fuel cells, solar cells, biomaterials, medicine, cosmetics and other fields, and are promoting the research and development of single-layer carbon nanotubes as transistors, fuel cells and hydrogen storage materials. With regard to cosmetics that have attracted much attention because nano-materials can be directly used in the skin, the Japan Federation of Industries made a report on the topic of "Nano-materials and cosmetics". The results of a questionnaire survey on cosmetics manufacturers and importers show that among 120 enterprises that use nano-materials as raw materials,15 (96%) use titanium oxide, 72 (60%) use zinc oxide and 26 (22%) use silicon dioxide. Mainly used for sun protection, but also as a foundation. Forty years ago, titanium oxide and zinc oxide were used together to prevent ultraviolet rays. Because the smaller the particle size, the higher the function, so they gradually become nano-materials. Japan Institute of Labor Safety and Health introduced the "Detection and Management Methods of Nanomaterials". Most methods for measuring nano-material particles in the air use aerosol detection method to measure the number and particle size distribution of particles in real time. The detection method detects the degree of light scattering. Used with grading equipment. The condensed state, morphology and composition are mainly observed by electron microscope, which can be accurately detected, but can not be measured in real time. Members from different professional fields asked the speaker questions and confirmed the basic data that will be the basis for future deliberations. After reaching an understanding, the seminar ended.
Question 5: Why do nanomaterials play such a big role? Nano-materials (also known as ultrafine particles and ultrafine powder) are typical systems in the transition zone between atomic clusters and macroscopic objects. Their structures are different from those of bulk materials and single atoms. Their special structural energy levels make them have surface effect, volume effect, quantum size effect and so on. , and has a series of novel physical and chemical properties, especially in many fields such as light, electricity, magnetism and catalysis.
The attractive characteristics of nano-materials in structure, photoelectric and chemical properties have aroused great interest of physicists, materials scientists and chemists. In the early 1980s, after the concept of nano-materials was formed, countries all over the world attached great importance to this material. Its unique physical and chemical properties make people realize that its development may bring new opportunities to the research of physics, chemistry, materials, biology, medicine and other disciplines. The application prospect of nano-materials is very broad. In recent years,
Application of 1. in catalysis
Catalysts play an important role in many chemical and chemical fields, which can control the reaction time and improve the reaction efficiency and speed. Most traditional catalysts not only have low catalytic efficiency, but also are prepared by experience, which not only causes huge waste of raw materials, but also pollutes the environment. There are many active centers on the surface of nanoparticles, which provides the necessary conditions for them to be used as catalysts. It can greatly improve the reaction efficiency, control the reaction speed, and even carry out reactions that could not be carried out before. The reaction speed of nano-particles as catalysts is 10 ~ 15 times higher than that of ordinary catalysts.
Semiconductor photocatalysts are widely used as catalysts, especially in the preparation of organic compounds. Each semiconductor particle dispersed in the solution can be approximately regarded as a short-circuited microbattery. When the semiconductor dispersion system is irradiated with light with energy greater than the energy gap of the semiconductor, the semiconductor nanoparticles absorb the light and produce electron-hole pairs. Under the action of electric field, electrons and holes are separated and moved to different positions on the surface of particles respectively, and redox reaction occurs with substances with similar components in solution.
Photocatalytic reaction involves many reaction types, such as oxidation of alcohols and hydrocarbons, oxidation and reduction of inorganic ions, catalytic dehydrogenation and hydrogenation of organic compounds, amino acid synthesis, nitrogen fixation, water purification treatment, water gas shift and so on. Some of them are difficult to realize by heterogeneous catalysis. Semiconductor heterogeneous photocatalyst can effectively degrade organic pollutants in water. For example, nano-titanium dioxide has high photocatalytic activity, acid and alkali resistance, light stability, non-toxic, cheap and easy to obtain. It is the best choice for preparing supported photocatalyst. It is reported that TiO/SiO _ 2 supported photocatalyst with high catalytic activity was prepared with silica gel as matrix. Nanoparticles of nickel or copper-zinc compounds are excellent catalysts for hydrogenation of some organic compounds. It can replace expensive platinum or button catalyst. Nano-platinum black catalyst can reduce the temperature of ethylene oxidation reaction from 600℃ to room temperature. Using nanoparticles as catalyst to improve the reaction efficiency, optimize the reaction path and improve the reaction speed is an important research topic that can not be ignored in the future catalytic science, which may bring revolutionary changes to the industrial application of catalysis.
2. Application in coatings
Because of its special surface and structure, nano-materials have excellent properties that are difficult to be obtained by ordinary materials, showing strong vitality. Surface coating technology is also a hot spot in the world today. Nano-materials provide a good opportunity for surface coating and make the functionalization of materials extremely possible. With the help of traditional coating technology and adding nano-materials, nano-composite coatings can be obtained, and the traditional coatings can be functionalized. Coatings can be divided into structural coatings and functional coatings according to their uses. Structural coating is a functional coating, which endows the substrate with properties that it does not have, thus obtaining functions that traditional coatings do not have. Structural coatings include superhard, wear-resistant coatings, oxidation-resistant, heat-resistant, flame-retardant coatings, corrosion-resistant and decorative coatings. Functional coatings include optical coatings with extinction, light reflection and light selective absorption, electrical coatings with conductivity, insulation and semiconductor properties, and sensitive coatings with oxygen sensitivity, humidity sensitivity and gas sensitivity. Adding nano-materials into coatings can further improve the protective ability of coatings, and realize the functions of anti-ultraviolet, anti-atmospheric invasion, anti-degradation and anti-discoloration. When used in sanitary products, it can play a role in sterilization and cleaning. Using nano-material coatings on signs can take advantage of their optical characteristics. & gt
Question 6: How to make nanomaterials? Nanotechnology includes the following four main aspects: 1, nanomaterials: when a substance reaches the nanometer level, which is about 0. 1- 100 nanometer, the properties of the substance will suddenly change and special properties will appear. This kind of material with special properties different from the original atoms, molecules and macroscopic substances is called nano-material. If only nano-scale materials have no special properties, they cannot be called nano-materials. In the past, people only paid attention to atoms, molecules or cosmic space, and often ignored this intermediate field, which actually exists in nature in large quantities, but did not realize the performance of this scale range before. Japanese scientists were the first to truly recognize its characteristics and introduce the concept of nano. In 1970s, they prepared ultramicro ions by evaporation, and found that a kind of conductive copper-silver conductor lost its original properties after being made into nano-scale, neither conducting electricity nor conducting heat. The same is true of magnetic materials, such as iron-cobalt alloys. If the size is about 20-30 nanometers, the magnetic domain will become a single magnetic domain, and its magnetism will be 1000 times higher than the original. In the mid-1980s, people formally named this kind of materials as nanomaterials. Why does the magnetic domain become a single magnetic domain, and its magnetism is 1000 times higher than the original one? This is because the arrangement of single atoms in a magnetic domain is not very regular, but there is a nucleus in the middle of a single atom surrounded by electrons, which is the reason for the formation of magnetism. However, after becoming a single magnetic domain, the single atoms are arranged regularly and show strong magnetism to the outside. This characteristic is mainly used to manufacture micro-motors. If the technology is developed for a certain period of time and used to manufacture magnetic levitation, a faster, more stable and more energy-saving high-speed train can be manufactured. Nano-dynamics, mainly micro-machinery and micro-motor, or micro-electromechanical system (MEMS), is used as micro-sensors and actuators for transmission machinery, optical fiber communication systems, special electronic equipment, medical and diagnostic instruments, etc. It adopts a new technology similar to the design and manufacture of integrated appliances. The feature is that the parts are very small, the etching depth often needs tens to hundreds of microns, and the width error is very small. This process can also be used to manufacture three-phase motors, ultra-high-speed centrifuges or gyroscopes. In the research, micro-deformation and micro-friction at quasi-atomic scale should be detected accordingly. Although they have not really entered the nanometer scale at present, they have great potential scientific and economic value. Theoretically, micro-motor and detection technology can reach nanometer level. 13. nano-biology and nano-pharmacology, such as fixing dna particles on mica surface with nano-sized colloidal gold, doing experiments on the interaction between biomolecules with interdigital electrodes on the surface of silica, double-layer planar biofilm of phospholipids and fatty acids, and fine structure of dna. With nanotechnology, you can also put parts or components into cells through self-assembly to form new materials. About half of the new drugs, even the fine powder of micron particles, are insoluble in water; However, if the particles are nanoscale (i.e. ultrafine particles), they can be dissolved in water. When nano-organisms develop to a certain technology, nano-biological cells with recognition ability can be made of nano-materials, and the biomedical absorption of cancer cells can be injected into the human body for targeted killing of cancer cells. (The above are old banknotes) 1. Nano-electronics includes nano-electronic devices based on quantum effect, optical/electrical characteristics of nanostructures, characterization of nano-electronic materials, and atomic manipulation and assembly. The current trend of electronic technology requires devices and systems to be smaller, faster, colder and smaller, which means faster response. Being colder means that a single device consumes less power. But smaller is not infinite. Nanotechnology is the last frontier of builders, and its influence will be enormous.
Question 7: What are nanomaterials? What is its connotation? Nano-materials refer to materials with at least one dimension or their basic units in three-dimensional space (0. 1- 100 nm), which is approximately equivalent to the scale where 10~ 100 atoms are closely arranged together.