1. Natural nanomaterials
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Sea turtles lay their eggs on the coast of Florida in the United States, but after birth, the young turtles have to swim to the waters near the United Kingdom in order to survive and grow up. Finally, the adult turtles return to the Florida coast to lay their eggs. It takes five to six years to make the trip, so why are turtles able to travel tens of thousands of kilometers? They rely on magnetic nanomaterials inside their heads to navigate them flawlessly.
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When biologists study why pigeons, dolphins, butterflies, bees and other organisms never lose their way, they also find nanomaterials in these organisms to guide them.
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2, nano magnetic materials
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Most of the nanomaterials used in practice are man-made. Nano-magnetic materials have very special magnetic properties, small size of nanoparticles, with a single magnetic domain structure and high coercivity characteristics, the magnetic recording materials made of it not only sound quality, image and signal to noise ratio is good, and the recording density is dozens of times higher than γ-Fe2O3. Superparamagnetic strong magnetic nanoparticles can also be made into magnetic liquids, which are used in electroacoustic devices, damping devices, rotary seals, lubrication and mineral processing.
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3. Nano-ceramic materials
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In traditional ceramic materials, the grain is not easy to slip, the material is brittle and the sintering temperature is high. Nano-ceramic grain size is small, the grain is easy to move on other grains, therefore, nano-ceramic materials have extremely high strength and high toughness and good ductility, these characteristics make nano-ceramic materials can be cold processed at room temperature or sub-high temperature. If the nano-ceramic particles are processed and formed at sub-high temperatures, and then the surface annealing treatment is done, the nanomaterial can be made into a high-performance ceramic whose surface maintains the hardness and chemical stability of conventional ceramic materials, while the interior still has the ductility of nanomaterial.
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4. Nanosensors
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Nano-zirconia, nickel oxide, titanium dioxide and other ceramics are very sensitive to temperature changes, infrared rays and automobile exhaust. Therefore, they can be used to make temperature sensors, infrared detectors and automobile exhaust detectors, and the detection sensitivity is much higher than that of ordinary similar ceramic sensors.
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5, nano tilt functional materials
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In aerospace hydrogen-oxygen engines, the inner surface of the combustion chamber needs to be resistant to high temperature, and the outer surface needs to be in contact with the coolant. Therefore, the inner surface should be made of ceramic, and the outer surface should be made of metal with good thermal conductivity. But lumpy ceramics and metals are difficult to combine. If the composition of the metal and ceramic is gradually changed continuously during production, the metal and ceramic are made. You have me, I have you " Eventually, they can be combined to form a tilted functional material, which means that the composition changes like a tilted ladder. When metal and ceramic nanoparticles are mixed and sintered according to the requirements of gradually changing content, the requirements of high temperature resistance on the inside of the combustion chamber and good thermal conductivity on the outside can be achieved.
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6, nano semiconductor materials
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Nanomaterials made from semiconductor materials such as silicon and gallium arsenide have many excellent properties. For example, the quantum tunneling effect in nanosemiconductors makes the electron transport of some semiconductor materials abnormal, the electrical conductivity decreases, and the electrical thermal conductivity decreases with the decrease of particle size, and even appears negative. These characteristics play an important role in the field of large-scale integrated circuit devices, optoelectronic devices and so on.
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Semiconductor nanoparticles can be used to produce a new type of solar cell with high photoelectric conversion efficiency, which can work normally even in rainy days. Because the electrons and holes produced by the nano semiconductor particles are irradiated by light have strong reduction and oxidation capacity, it can oxidize toxic inorganic substances, degrade most organic matter, and eventually generate non-toxic, odorless carbon dioxide, water, etc., so you can use semiconductor nanoparticles to catalyze the decomposition of inorganic substances and organic matter.
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7, nano catalytic materials
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Nanoparticles are an excellent catalyst, which is due to the small size of nanoparticles, the larger volume fraction of the surface, the chemical bond state and electronic state of the surface are different from the particle inside, and the incomplete coordination of the surface atoms, resulting in an increase in the active position of the surface, so that it has the basic conditions as a catalyst.
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The hydrogenation of certain organics by nanoparticles of nickel or copper-zinc compounds is an excellent catalyst that can replace expensive platinum or palladium catalysts. The nano-platinum black catalyst can reduce the temperature of ethylene oxidation from 600 ℃ to room temperature.
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8. Medical applications
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The size of the red blood cells in the blood is 6 000 to 9 000 nm, while the nanoparticles are only a few nanometers in size, and are actually much smaller than the red blood cells, so it can move freely in the blood. If various therapeutic nanoparticles are injected into various parts of the human body, lesions can be examined and treated, and its effect is better than the traditional injection and medicine