1, nanometer is the unit of measurement for geometric dimensions, 1 nanometer = one millionth of a millimeter.
2. Nanotechnology has promoted the technological revolution.
3. Drugs made by nanotechnology can block capillaries and "starve" cancer cells.
4. If nano-integrated devices are used on the satellite, the satellite will be smaller and easier to launch.
Nanotechnology is a synthesis of many sciences, and some goals take a long time to achieve.
6. Nanotechnology, information science and technology and life science and technology are the mainstream of current scientific development, and their development will make human society, living environment and science and technology itself better.
7. Nanotechnology can observe the pathological changes and conditions of cancer cells in patients, so that doctors can prescribe the right medicine. Nano-scale measurement technology includes: precise measurement of nano-scale size and displacement, nano-scale surface morphology measurement. There are two main development directions of nano-scale measurement technology.
One is optical interferometry, which uses interference fringes of light to improve the resolution of measurement. Its measurement methods include: dual-frequency laser interferometry, optical heterodyne interferometry, X-ray interferometry, F-P standard tool measurement and so on. It can be used for accurate measurement of length and displacement, and also for measurement of surface micro-morphology.
The second is scanning probe microscopy (STM), whose basic principle is tunneling effect based on quantum mechanics. Its principle is to scan the measured surface with a very sharp probe (or similar method) (the probe is not actually in contact with the measured surface), and measure the three-dimensional micro-stereoscopic morphology of the surface with the help of a nano-scale three-dimensional displacement positioning control system. It is mainly used to measure the micro-morphology and size of the surface.
The measurement methods using this principle include scanning tunneling microscope (STM) and atomic microscope (AFM). Nano-scale machining refers to machining technology with nano-scale precision.
Because the distance between atoms is 0. 1-0.3nm, the essence of nano-machining is to cut off the bonding between atoms and realize the removal of atoms or molecules, and the energy required to cut off the bonding between atoms must exceed the bonding energy between atoms, that is, the energy density of planting is very large. It is quite difficult to process nano-scale by traditional cutting and grinding methods. By 2008, there has been a great breakthrough in nano-processing. For example, when processing VLSI by electron beam lithography (UGA technology), the processing of line width of 0. 1μm can be realized; Ion etching can remove micro-scale and nano-scale surface materials; Scanning tunneling microscopy can remove, distort, add and recombine individual atoms. There are many methods to prepare nanoparticles, which can be divided into physical methods and chemical methods.
Clothing made of nanotechnology
Vacuum cold feeding method: raw materials are vaporized or formed into particles by vacuum evaporation, heating and high frequency induction, and then quenched. Its characteristics are high purity, good crystal structure and controllable degree, but it requires high technical equipment.
Physical crushing method: Nanoparticles are obtained by mechanical crushing, electric spark explosion and other methods. It is characterized by simple operation and low cost, but the crystal product has low purity and uneven distribution along the grain.
Mechanical ball milling method: the nano-particles of pure elements, alloys or composite materials are obtained by ball milling method and controlling appropriate conditions. Its characteristics are simple operation and low cost, but the product purity is low and the particle distribution is uneven.
Vapor deposition method: synthesis of nano-materials by chemical reaction of metal compound vapor. It is characterized by high product purity and narrow particle size distribution.
Precipitation method: adding precipitant into salt solution for reaction, and then heat treating the precipitate to obtain nano-materials. It is characterized by simplicity, low purity and large particle size, and is suitable for preparing carriers. Hydrothermal synthesis method: synthesis in high temperature and high pressure aqueous solution or steam, then separation and heat treatment to obtain nanoparticles. Its characteristics are high purity, good dispersibility and easy control of tensile strength.
Sol-gel method: metal compounds are solidified by solution, sol and gel, and then heat-treated at low temperature to produce nanoparticles. It is characterized by many reaction species, uniform product particles and easy control of the process, and is suitable for the preparation of oxides and 1 1-VI compounds.
Hui emulsion method: 2. Insoluble solvent forms emulsion under the action of surfactant, and nanoparticles are obtained after nucleation, agglomeration, coagulation and heat treatment in Hui foam. Its characteristic particles have good monodispersity and interface, and 1 1-VI semiconductor nanoparticles are mostly prepared by this method.
Hydrothermal synthesis-synthesis at high temperature and high pressure in water solution or steam, and then separation and heat treatment to obtain nanoparticles. Its characteristics are high purity, good dispersibility and easy control of particle size. Since Gleiter and others took the lead in preparing nanomaterials in 199 1 year, after the development of1year, nanomaterials have made great progress. At present, there are many kinds of nano-materials, including metal materials, nano-ceramic materials, nano-semiconductor materials, nano-composite materials, nano-polymer materials and so on. Nano-materials are super-granular materials, which are called "new materials of 2 1 century" and have many special properties.
For example, the strength and hardness of the material sintered from nano-sized metal powder are much higher than the original metal, and the nano-sized metal has actually changed from a conductor to an insulator. Ordinary ceramics are fragile. However, ceramics sintered by nano-powder have not only high strength, but also good toughness. The melting point of nano-materials will decrease with the decrease of the diameter of ultrafine powder. For example, the melting point of gold is 1064℃, but the melting point of gold powder of 10nm is reduced to 940℃, and the melting point of gold powder of snm is reduced to 830℃, which can greatly reduce the sintering temperature. The sintering temperature of nano-ceramics is much lower than that of original ceramics. Nano-catalyst is added to gasoline. The efficiency of the internal combustion engine can be improved.
Adding solid fuel can accelerate the rocket. The medicine is made into nanometer powder. It can be injected into blood vessels and smoothly enter microvessels. At present, conventional imaging technology can only detect the visible changes caused by cancer in tissues, and at this time, thousands of cancer cells have been generated and may metastasize. Moreover, even if the tumor can already be seen, due to the category (malignant or benign) and characteristics of the tumor itself, it is necessary to determine the effective treatment method through biopsy. If cancer cells or precancerous cells are labeled in some way, they can be detected by traditional equipment, which is more conducive to the diagnosis of cancer.
To achieve this goal, there are two necessary conditions: a technology can specifically identify cancer cells and make the identified cancer cells visible. Nanotechnology can satisfy these two points. For example, the surface of metal oxide is coated with antibody, which can specifically recognize the receptor over-expressed on the surface of cancer cells. Because metal oxides emit high contrast signals under magnetic resonance imaging (MRI) or computed tomography (CT), once they enter the body, the antibodies on the surface of these metal oxide nanoparticles will selectively bind to cancer cells, so that the detection instrument can effectively identify cancer cells. Similarly, gold nanoparticles can also be used to enhance light scattering in endoscopic technology. Nanotechnology can visualize molecular markers that identify cancer types and different stages of development, so that doctors can see cells and molecules that cannot be detected by traditional imaging techniques.
In the fight against cancer, half the victories are due to early detection. Nanotechnology makes the diagnosis of cancer earlier and more accurate, and can be used for treatment monitoring. Nanotechnology can also enhance or even revolutionize the screening of biomarkers in tissues and body fluids. Because of the differences in the expression and distribution of various molecules, there are differences between cancer and cancer and between cancer cells and normal cells. With the development of treatment technology, it is necessary to detect multiple cancer biomarkers at the same time when determining the treatment plan. Nanoparticles, such as quantum dots, can emit different colors of light according to their own size, and can achieve the purpose of simultaneously detecting multiple markers. The excitation light signal emitted by quantum dots coated with antibodies can be used to screen some types of cancer. Quantum dots with different colors can bind to various cancer biomarker antibodies, which is convenient for oncologists to distinguish cancer cells from healthy cells by the spectrum they see. As the etching technology has reached the limit on the nanometer scale, assembly technology will become an important means of nanotechnology, which has attracted great attention.
Nanoassembly technology is to assemble atoms, molecules or molecular aggregates by mechanical, physical, chemical or biological methods to form functional structural units. Assembly technology includes molecular ordered assembly technology, scanning probe atom, molecular repositioning technology and biological assembly technology. Ordered molecular assembly is to form an ordered two-dimensional or three-dimensional molecular system through physical or chemical interaction between molecules. At present, the latest progress of molecular ordered assembly technology and its application research is mainly the research of LB film and the discovery of related characteristics. Recognition and assembly of biological macromolecules. The assembly of bioactive macromolecules such as protein and nucleic acid requires quotient density orientation, which is very important for preparing high-performance biosensors, developing biomolecular devices and studying the interaction between biomacromolecules. In the process of assembling lgG biomacromolecules, the recognition function of antibody active fragments was used to assemble active biomacromolecules for the first time. This important progress has made a new breakthrough in the directional assembly of biomolecules.
In addition to the above-mentioned assembly, the ordered assembly of long-chain polymer molecules, bridging self-assembly technology and the application of ordered molecular films have also made progress. Nano-machining technology can also be used to process materials at atomic level, which makes the processing technology enter a more detailed depth. The development of nanostructure self-assembly technology will make breakthroughs in nano-machinery, nano-electromechanical systems and nano-biology.
China has certain advantages in scientific discovery and industrialization research in the field of nanotechnology. Modern countries such as the United States, Japan and Germany are at the forefront of the international first echelon. Although a certain number of production bases of nano-materials have been established in modern China, the development and application of nano-technology have also risen and initially realized industrialization. There is still a lot of work to be done to realize the large-scale and low-cost industrial production of nano, and only by relying on a lot of capital and high-tech investment can we get high profit returns. Nanobiology is to study the structure and function of various organelles in cells on the nanometer scale. Study the exchange of matter, energy and information within cells and between cells and the whole organism. The research of nanobiology mainly focuses on the following aspects.
Great progress has been made in DNA research in three aspects: morphological observation, characteristic research and genetic modification.
Brain function research
The goal of the work is to find out the advanced neurological functions of human memory, thinking, language and learning and the information processing functions of human brain.
Bionics research
This is a hot research content of nanobiology. A lot of achievements have been made now. This is a promising part of nanotechnology.
The smallest motor in the world is a biological motor-flagella motor. It can rotate like a propeller to drive the flagella to rotate. Motor is usually composed of 10 protein population, and its structure is like an artificial motor. It consists of stator, rotor, bearing and universal joint. Its diameter is only 3nm, the rotating speed can be as high as 15r/min, and the right turn and left turn can be switched in 1 μ s ... Acceleration or deceleration can be realized by using external electric field. The power source of rotation is the concentration difference of nitrogen and oxygen ions inside and outside the membrane supporting the motor in bacteria. Experiments prove that. The potential difference inside and outside the bacteria can also drive the flagella motor. Modern people are exploring to design an artificial flagella motor driver that can be controlled by potential difference.
Mitsubishi Corporation of Japan has developed a retina chip, which can simulate the function of human eyes in processing visual images. The chip is based on arsenic semiconductor. Each chip contains 4096 sensing elements. It is expected to be further applied to robots.
It is proposed to make molecular machines like rings and rods. Assemble them into circuit units of a computer. The unit size is only Inm, and it can be assembled into a subminiature computer with a volume of only a few microns, which can achieve the same performance as modern common computers.
In the manufacture of nano-structured self-assembled complex electromechanical systems, a big problem is the assembly of various components in the system. The more advanced and complex the system is, the more difficult it is to solve the assembly problem. Protein, DNA, cells, etc. All kinds of creatures in nature have extremely complex structures. Their generation and assembly are automatic. If we can understand and control the self-assembly principle of biological macromolecules, human understanding and transformation of nature will inevitably rise to a brand-new and higher level.