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About Stealth Materials and Related Nano Materials

Stealth materials, also known as absorbing materials, refer to a type of electromagnetic material that can absorb and attenuate incident electromagnetic waves, convert electromagnetic energy into heat energy, and consume it. They are widely used in military, aerospace, and security fields to reduce the detectability of targets in equipment such as electromagnetic wave detectors, radar systems, and infrared sensors.

 

The principle of stealth materials mainly includes two aspects:

 

Absorption: Stealth materials have the characteristic of highly absorbing electromagnetic waves, which can absorb most or specific wavelengths of light within the spectral range, thereby reducing reflection and scattering. This absorption characteristic can be achieved through appropriate material selection and design, such as using composite materials with absorbing agents or absorbing coatings.

 

Scattering: Stealth materials can change the propagation path of electromagnetic waves by causing them to scatter or refract in different directions, thereby reducing the echo signal of the target. This principle can be achieved through the design of nanostructures, microstructures, or multi-layer materials to alter the interaction between electromagnetic waves and materials.

 

The common nano powder used for stealth applications include iron oxide, nano silver, and so on. They have excellent absorption and scattering characteristics, effectively weaken or shield the reflection and echo signals of electromagnetic waves, and improve the stealth performance of targets. The following are some common applications of nano powders in stealth technology:

 

  1. Iron oxide nano powder: Iron oxide nano powder has excellent wave absorption performance, can absorb and scatter electromagnetic waves, and achieve stealth effect within a certain range.

 

  1. Carbon nanotubes: Carbon nanotubes have high conductivity and good absorption properties, which can absorb and dissipate electromagnetic waves over a wide frequency range. They are used to prepare composite materials with good stealth properties.

 

  1. Graphene: As a two-dimensional material with a single layer of carbon atoms, graphene has excellent electron transfer and absorption properties and can be used to prepare efficient invisible coatings or composite materials.

 

  1. Silver nanoparticles: Silver nanoparticles exhibit excellent absorption performance in the visible light range, capable of absorbing, scattering, or reflecting electromagnetic waves, achieving stealth effects.

 

The above-mentioned nano raw materials are all supplied by Hongwu Nano. Welcome to contact us for further information if you are interested in.

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Effect of Nanopowder on Agricultural Expelling Insect

Nanomaterials have broad application potential in insect repellent agriculture. The following are some common examples of nano powders that may play a role in agricultural pest control:

 

  1. Silica nanoparticles(HW-A213): Silica nanoparticles are widely used in agriculture as an environmentally friendly pesticide. They can adsorb on the surface of insect shells, damage the protective layer of the insect body, and cause dehydration, suffocation, or death of the insect.

 

  1. Metal oxide nano powder: metal oxide nano powder, such as silicon dioxide (HW-T681&T689) and zinc dioxide (HW-Z713), has the effect of insecticide. They can kill insects by photocatalysis, activate the surface of nano powder by ultraviolet radiation, produce free radicals or oxides, and cause damage to insects.

 

  1. Carbon nanotubes(HW-C931): Carbon nanotubes have a large surface area and high mechanical strength. They can be used as carriers to load insecticides onto their surfaces and improve insecticidal efficacy by controlling release. In addition, carbon nanotubes can also be used as insect sensors to monitor and control pests by detecting chemical signals released by insects.

 

  1. Nano boron nitride(HW-L551): Nano boron nitride has excellent thermal conductivity and stability, and can be used to develop efficient fire-resistant materials. In agriculture, it can also be used as an insecticide to control pests through physical effects or interference with the normal physiological activities of insects.

 

  1. Nanographene(HW-C952): Nanographene is a nanomaterial with excellent conductivity and photothermal properties. It can be applied to the electric insecticidal mechanism, which kills pests by heating. Nanographene can generate high temperatures at lower currents, causing fatal damage to agricultural pests.

 

The application of nano powder in agricultural insecticide is mainly reflected in the use of nano pesticide. Nanopesticides are the use of nanotechnology to prepare pesticide active ingredients into nanoscale particles, in order to enhance their solubility, dispersibility, and activity, improve the effectiveness and utilization of pesticides, and ensure their safety and environmental friendliness. In addition, scientific and reasonable agricultural management and the application of comprehensive prevention and control measures remain the key to promoting sustainable agricultural development.

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Two common anti-UV materials: nano titanium dioxide (TiO2) and nano zinc oxide (ZnO)

Nano zinc oxide (ZnO) and nano titanium dioxide (TiO2) are two commonly-used oxide materials for UV resistance.

 

They have special optical and chemical properties at the nanoscale, making them important candidates in the field of UV resistance.

 

  1. Nanozinc oxide (ZnO), as an excellent ultraviolet shielding agent, shows good ultraviolet absorption properties in the ultraviolet spectrum range. It has high transmittance and excellent optical properties, so it is widely used in the preparation of anti-UVcoatings, fabrics and other products as it has a shielding effect on both UVA (long wave 320 ~ 400nm) and UVB (medium wave 280 ~ 320nm).

 

  1. Nanotitanium dioxide(TiO2)has excellent chemical stability, thermal stability and non-migration, strong achromatic and hiding power, low corrosiveness, good dispersibility, and is non-toxic, odorless and non-irritating, safe to use, and also has the function of sterilization and deodorization.

 

More importantly, nano titanium dioxide can not only absorb ultraviolet rays, but also emit and scatter ultraviolet rays, so it has strong UV resistance. Compared with the same dose of organic anti-UV agents, its absorption peak in the ultraviolet region is higher. Moreover, nano TiO2 has a blocking effect on both medium-wave and long-wave ultraviolet rays, unlike organic anti-UV agents that only have a shielding effect on medium-wave or long-wave ultraviolet rays. Researchers add light shielding agents, light stabilizers, etc. to achieve photoaging resistance of polymer material products, and rutile-type nano TiO2 is non-toxic and odorless to ultraviolet light UVA (315 ~ 400 nm) and UVB (280 ~ 315 nm) ) have a very good shielding effect, do not decompose or discolor after absorbing ultraviolet light, and have excellent stability and durability.

 

  1. The combined use of zinc oxidenano and titanium dioxide nano is also a common anti-UV strategy. Their combined use can give full play to their respective advantages and improve the anti-ultraviolet effect.

Since a single oxide absorbs ultraviolet light in a limited wavelength range, the preparation of UV-resistant nanocomposite oxides has attracted increasing attention from researchers.

For example, nano titania mainly has good absorption performance at 280~350nm, but its absorption at 350~400nm is weak. Although nano ZnO’s short-wave absorption performance is not as good as nano TiO2, it can provide very broad-spectrum protection and inhibit UVA.

The experimental results were found through the ultraviolet absorption spectrum of pure TiO2 and nano ZnO/TiO2 composite particles: at the same concentration, the ultraviolet transmittance of the system containing nano-TiO2 in the 280 ~ 322nm band is only 1%, and the ultraviolet transmittance in the 322 ~ 351nm band is only 1%. The transmittance is 1%~15%, the ultraviolet transmittance in the 351~400nm band is 15%~46%, and its ultraviolet transmittance in the 322~400nm band shows a linear upward trend; while the ultraviolet transmittance of nano-ZnO/TiO2 composite particles in the range of 280-351nm band is always 15%, and the transmittance in the 351 ~ 400nm band is only 15%-18%, the increase in ultraviolet transmittance is not significant.

It can be seen that the UV shielding performance of nano-TiO2 below 351nm is higher than that of nano-ZnO/TiO2, while above 351nm, the UV-shielding performance of nano-ZnO/TiO2 is much higher than nano-TiO2. Although the absorption of nano-ZnO/TiO2 in the UVB region is not as good as that of nano TiO2, its blocking effect on long-wave UVA is better than that of nano-TiO2. It can also be seen that the ultraviolet transmittance of the composite particles in the entire UVB and UVA bands is very small, always below 15%, knowing that this composite particle has a strong ability to shield ultraviolet rays.

 

To sum up, nano zinc oxide and nano titanium dioxide play an important role in the field of UV resistance. Their excellent performance and wide application make them key ingredients in protective products, providing effective protection for people’s health and safety.

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Nano Materials applied in flexible screens

The beauty of flexibility is everywhere. The development of flexible screens can be applied to all walks of life, make life more concise and convenient. Here are some nano materials that can be used for flexible screens:

ITO nanopowder

ITO (tin oxidation) transparent conductive film has become the most important touch layer material for display screens such as non -curved LCD and OLED due to many reasons such as good light transmission, low thickness, excellent hardness and electrical conductivity, and mature production process. However, ITO is a kind of crispy material, not suitable for the flexible touch layer that can be curved or even bent at will, and the cost is high.

Nano graphene, carbon nanotubes, silver nanowires, etc.

At present, the main substitutes for ITO materials are: nano graphene, carbon nanotubes, silver nano wires, and metal grids. Among them, nano graphene and carbon nanotubes are very good substitutes for ITO in terms of material itself. But graphene is still a bit far from mass production. The film made of nano -carbon tube is not as good as ITO in conductivity. Therefore, from the perspective of technology and market, metal grids and nano -silver technology will be the protagonist of recent development.

The metal grid technology mentioned here is the conductive metal mesh formed by using metal conductive materials such as silver and copper or oxides on PET and other thin film substrates. Its main advantage is that the cost of raw materials is low and good for winding. However, due to the problem of Morri interference ripples caused by good rate, yield and high -end high pixels, it is more suitable for applications with low resolution and relatively long -distance use. Desktop all -in -one machines, laptops and television products.

Nano -silver wire technology refers to applying nano -silver wire ink materials to PET or glass substrates, and then uses Laser lithography technology to portray the nano -level conductive network. Its main advantages are high rates, small line width, good conductivity and resistance, and disadvantages are high costs. And compared to metal grids, nano -silver materials have a small curvature radius, and the resistance changing rate of resistance during bending is small, plus the reasons for the width, so it is more suitable for high -resolution such as mobile phones, smart watches and bracelets. Use in close range scenes.