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One-step synthesis of photoluminescent catalytic gold nanoclusters using organoselenium compounds. Yasser A. Abdel-Hafez bc. You have access to this article. Please wait while we load your content Something went wrong. Try again?
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Carbon nanotubes hold great potential for science and technology. NASA, for example, is experimenting with carbon nanotubes to produce "blacker than black" coloration on satellite s. This would reduce reflection, so data collected by the satellite are not "polluted" by light. Nanoparticles can include carbon, like fullerenes, as well as nanometer-scale versions of many other elements, such as gold, silicon, and titanium.
Quantum dot s, a type of nanoparticle, are semiconductor s made of different elements, including cadmium and sulfur. Quantum dots have unusual fluorescent capabilities.
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Scientists and engineers have experimented with using quantum dots in everything from photovoltaic cells used for solar power to fabric dye. The properties of nanoparticles have been important in the study of nanomedicine. One promising development in nanomedicine is the use of gold nanoparticles to fight lymphoma , a type of cancer that attacks cholesterol cells. Researchers have developed a nanoparticle that looks like a cholesterol cell, but with gold at its core.
When this nanoparticle attaches to a lymphoma cell, it prevents the lymphoma from "feeding" off actual cholesterol cells, starving it to death.
Nanoparticles and Catalysis - Nanoparticles and Catalysis - Wiley Online Library
There are four main types of intentionally produced nanomaterials: carbon-based, metal-based, dendrimers, and nanocomposites. Carbon-based nanomaterials are intentionally produced fullerenes. These include carbon nanotubes and buckyballs. Carbon nanotubes are often produced using a process called carbon assisted vapor deposition. This is the process NASA uses to create its "blacker than black" satellite color. In this process, scientists establish a substrate , or base material, where the nanotubes grow. Silicon is a common substrate. Then, a catalyst helps the chemical reaction that grows the nanotubes.
Iron is a common catalyst. Finally, the process requires a heated gas, blown over the substrate and catalyst. The gas contains the carbon that grows into nanotubes. Quantum dots are synthesize d using different methods. In one method, small crystals of two different elements are formed under high temperatures. By controlling the temperature and other conditions, the size of the nanometer-scale crystals can be carefully controlled.
The size is what determines the fluorescent color. These nanocrystals are quantum dots—tiny semiconductors—suspended in a solution. Dendrimer s are complex nanoparticles built from linked, branched units. Each dendrimer has three sections: a core, an inner shell, and an outer shell. In addition, each dendrimer has branched ends. Each part of a dendrimer—its core, inner shell, outer shell, and branched ends—can be designed to perform a specific chemical function.prorarbysvila.gq
Dendrimers can be fabricate d either from the core outward divergent method or from the outer shell inward convergent method. Like buckyballs and some other nanomaterials, dendrimers have strong, cage-like cavities in their structure. Scientists and researchers are experimenting with dendrimers as multi-functional drug-delivery methods. A single dendrimer, for example, may deliver a drug to a specific cell, and also trace that drug's impact on the surrounding tissue. Nanocomposites combine nanomaterials with other nanomaterials, or with larger, bulk materials.
NCMCs, sometimes called nanoclay s, are often used to coat packing materials. MMC s are stronger and lighter than bulk metals. MMCs may be used to reduce heat in computer "server farms" or build vehicles light enough to airlift. Industrial plastics are often composed of PMCs. One promising area of nanomedical research is creating PMC "tissue scaffolding. This could revolutionize the treatment of burn injuries and organ loss. Scientists and engineers working at the nanometer-scale need special microscope s.
The atomic force microscope AFM and the scanning tunneling microscope STM are essential in the study of nanotechnology. These powerful tools allow scientists and engineers to see and manipulate individual atoms. AFMs use a very small probe —a cantilever with a tiny tip—to scan a nanostructure. The tip is only nanometers in diameter. As the tip is brought close to the sample being examined, the cantilever moves because of the atomic forces between the tip and the surface of the sample.
The tip moves up and down to keep both the signal and the distance from the sample constant. AFMs and STMs allow researchers to create an image of an individual atom or molecule that looks just like a topographic map. Top-down nanomanufacturing involves carving bulk materials to create features with nanometer-scale dimensions. For decades, the process used to produce computer chips has been top-down. Producers work to increase the speed and efficiency of each "generation" of microchip. The manufacture of graphene-based as opposed to silicon-based microchips may revolutionize the industry.
Bottom-up nanomanufacturing builds products atom-by-atom or molecule-by-molecule. Experimenting with quantum dots and other nanomaterials, tech companies are starting to develop transistor s and other electronic devices using individual molecules. These atom-thick transistors may mark the future development of the microchip industry. American physicist Richard Feynman is considered the father of nanotechnology. Modern nanotechnology truly began in , when the scanning tunneling microscope allowed scientists and engineers to see and manipulate individual atoms. The Binnig and Rohrer Nanotechnology Center in Zurich, Switzerland, continues to build on the work of these pioneering scientists by conducting research and developing new applications for nanotechnology.
By the end of the 20th century, many companies and governments were investing in nanotechnology. Major nanotech discoveries, such as carbon nanotubes, were made throughout the s. By the early s, nanomaterials were being used in consumer products from sports equipment to digital cameras. Modern nanotechnology may be quite new, but nanometer-scale materials have been used for centuries. As early as the 4th century, Roman artists had discovered that adding gold and silver to glass created a startling effect: The glass appeared slate green when lit from the outside, but glowed red when lit from within.
Nanoparticles of gold and silver were suspended in the glass solution, coloring it. The most famous surviving example of this technique is a ceremonial vessel , the Lycurgus Cup. Artists from China, western Asia, and Europe were also using nanoparticles of silver and copper, this time in pottery glazes. This gave a distinctive " luster " to ceramic s such as tiles and bowls.
In , modern microscopy revealed the technology of " Damascus steel ," a metal used in South Asia and the Middle East until the technique was lost in the 18th century—carbon nanotubes. Swords made with Damascus steel are legendary for their strength, durability, and ability to maintain a very sharp edge. One of the most well-known examples of pre-modern use of nanomaterials is in European medieval stained-glass windows.
Like the Romans before them, medieval artisans knew that by putting varying, small amounts of gold and silver in glass, they could produce bright reds and yellows. Many government s, scientists, and engineers are researching the potential of nanotechnology to bring affordable, high-tech, and energy-efficient products to millions of people around the world. Nanotechnology has improved the design of products such as light bulbs, paints, computer screens, and fuels. Nanotechnology is helping inform the development of alternative energy sources, such as solar and wind power.
Solar cells, for instance, turn sunlight into electric current s. Nanotechnology could change the way solar cells are used, making them more efficient and affordable. Solar cells, also called photovoltaic cells, are usually assembled as a series of large, flat panels. These solar panels are big and bulky. Email address for updates. My profile My library Metrics Alerts.