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Nanostructures
A nanostructure is a structure of intermediate size between microscopic and molecular structure A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...s. Nanostructural detail is microstructure at nanoscale. In describing nanostructures, it is necessary to differentiate between the number of dimensions in the volume of an object which are on the nanoscale. Nanotextured surfaces have ''one dimension'' on the nanoscale, i.e., only the thickness of the surface of an object is between 0.1 and 100 nm. Nanotubes have ''two dimensions'' on the nanoscale, i.e., the diameter of the tube is between 0.1 and 100 nm; its length can be far more. Finally, spherical nanoparticles have ''three dimensions'' on the nanoscale, i.e., the particle is between 0.1 and 100 nm in each spat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanoparticle
A nanoparticle or ultrafine particle is a particle of matter 1 to 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100 nm in only two directions. At the lowest range, metal particles smaller than 1 nm are usually called atom clusters instead. Nanoparticles are distinguished from microparticles (1-1000 μm), "fine particles" (sized between 100 and 2500 nm), and "coarse particles" (ranging from 2500 to 10,000 nm), because their smaller size drives very different physical or chemical properties, like colloidal properties and ultrafast optical effects or electric properties. Being more subject to the Brownian motion, they usually do not sediment, like colloid, colloidal particles that conversely are usually understood to range from 1 to 1000 nm. Being much smaller than the wavelengths of visible light (400-700 nm), nanoparticles cannot be seen with ordinary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-assembly
Self-assembly is a process in which a disordered system of pre-existing components forms an organized structure or pattern as a consequence of specific, local interactions among the components themselves, without external direction. When the constitutive components are molecules, the process is termed molecular self-assembly. Self-assembly can be classified as either static or dynamic. In ''static'' self-assembly, the ordered state forms as a system approaches equilibrium, reducing its free energy. However, in ''dynamic'' self-assembly, patterns of pre-existing components organized by specific local interactions are not commonly described as "self-assembled" by scientists in the associated disciplines. These structures are better described as " self-organized", although these terms are often used interchangeably. In chemistry and materials science Self-assembly in the classic sense can be defined as ''the spontaneous and reversible organization of molecular units in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanocomposite
Nanocomposite is a multiphase solid material where one of the phases has one, two or three dimensions of less than 100 nanometers (nm) or structures having nano-scale repeat distances between the different phases that make up the material. In the broadest sense this definition can include porous media, colloids, gels and copolymers, but is more usually taken to mean the solid combination of a bulk matrix and nano-dimensional phase(s) differing in properties due to dissimilarities in structure and chemistry. The mechanical, electrical, thermal, optical, electrochemical, catalytic properties of the nanocomposite will differ markedly from that of the component materials. Size limits for these effects have been proposed: in Kelly, A, ''Concise encyclopedia of composites materials'', Elsevier Science Ltd, 1994 #<5 nm for catalytic activity #<20 nm for making a hard magnetic material soft #<50 nm for refractive index changes #<100 nm for achieving superparamagnetism, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanohole
Nanoholes are a class of nanostructured material consisting of nanoscale voids in a surface of a material. Not to be confused with nanofoam or nanoporous materials which support a network of voids permeating throughout the material (often in a disordered state), nanohole materials feature a regular hole pattern extending through a single surface. These can be thought of as the inverse of a nanopillar or nanowire structure. Uses Nanohole structures have been used for a variety of applications, ranging from superlenses produced from a metal nanohole array, to structured photovoltaic devices used to improve carrier extraction, and light absorption. Nanohole structures are also extensively utilized for the creation of photonic crystals, particularly for creating photonic crystal Waveguide (optics), waveguides. See also *Nanoporous, Nanoporous material *Nanopore *Nanostructures References [Baidu] |
Ultrafine Particle
Ultrafine particles (UFPs) are particulate matter of nanoscale size (less than 0.1 μm or 100 nm in diameter). Regulations do not exist for this size class of ambient air pollution particles, which are far smaller than the regulated PM10 and PM2.5 particle classes and are believed to have several more aggressive health implications than those classes of larger particulates. Although they remain largely unregulated, the World Health Organization has published good practice statements regarding measuring UFPs. There are two main divisions that categorize types of UFPs. UFPs can either be carbon-based or metallic, and then can be further subdivided by their magnetic properties. Electron microscopy and special physical lab conditions allow scientists to observe UFP morphology. Airborne UFPs can be measured using a condensation particle counter, in which particles are mixed with alcohol vapor and then cooled, allowing the vapor to condense around them, after which they are count ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanowire
file:[email protected], upright=1.2, Crystalline 2×2-atom tin selenide nanowire grown inside a single-wall carbon nanotube (tube diameter ≈1 nm). A nanowire is a nanostructure in the form of a wire with the diameter of the order of a nanometre (10−9 m). More generally, nanowires can be defined as structures that have a thickness or diameter constrained to tens of nanometers or less and an unconstrained length. At these scales, quantum mechanical effects are important—which coined the term "quantum wires". Many different types of nanowires exist, including superconducting (e.g. Yttrium barium copper oxide, YBCO), metallic (e.g. nickel, Ni, platinum, Pt, gold, Au, silver, Ag), semiconducting (e.g. Silicon nanowire, silicon nanowires (SiNWs), indium phosphide, InP, gallium nitride, GaN) and insulating (e.g. Silicon dioxide, SiO2, Titanium dioxide, TiO2). Molecular nanowires are composed of repeating molecular units either organic (e.g. DNA) or inorganic (e.g. Mo6S9−''x'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanoscopic Scale
Nanotechnology is the manipulation of matter with at least one dimension sized from 1 to 100 nanometers (nm). At this scale, commonly known as the nanoscale, surface area and quantum mechanical effects become important in describing properties of matter. This definition of nanotechnology includes all types of research and technologies that deal with these special properties. It is common to see the plural form "nanotechnologies" as well as "nanoscale technologies" to refer to research and applications whose common trait is scale. An earlier understanding of nanotechnology referred to the particular technological goal of precisely manipulating atoms and molecules for fabricating macroscale products, now referred to as molecular nanotechnology. Nanotechnology defined by scale includes fields of science such as surface science, organic chemistry, molecular biology, semiconductor physics, energy storage, engineering, microfabrication, and molecular engineering. The associated rese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanosheet
A nanosheet is a two-dimensional nanostructure with thickness in a scale ranging from 1 to 100 nm. A typical example of a nanosheet is graphene, the thinnest two-dimensional material (0.34 nm) in the world. It consists of a single layer of carbon atoms with hexagonal lattices. Examples and applications , silicon nanosheets were being used to prototype future generations of small (5 nm) transistors. Carbon nanosheets (from hemp) may be an alternative to graphene as electrodes in supercapacitors. Synthesis The most commonly used nanosheet synthesis methods use a bottom-up approach, e.g., pre-organization and polymerization at interfaces like Langmuir–Blodgett films, solution phase synthesis and chemical vapor deposition (CVD). For example, CdTe (cadmium telluride) nanosheets could be synthesized by precipitating and aging CdTe nanoparticles in deionized water. The formation of free-floating CdTe nanosheets was due to directional hydrophobic attraction and anis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanoshell
A nanoshell, or rather a nanoshell plasmon, is a type of spherical nanoparticle consisting of a dielectric core which is covered by a thin metallic shell (usually gold). These nanoshells involve a quasiparticle called a plasmon which is a collective excitation or quantum plasma oscillation where the electrons simultaneously oscillate with respect to all the ions. The simultaneous oscillation can be called plasmon hybridization where the tunability of the oscillation is associated with mixture of the inner and outer shell where they hybridize to give a lower energy or higher energy. This lower energy couples strongly to incident light, whereas the higher energy is an anti-bonding and weakly combines to incident light. The hybridization interaction is stronger for thinner shell layers, hence, the thickness of the shell and overall particle radius determines which wavelength of light it couples with. Nanoshells can be varied across a broad range of the light spectrum that spans the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanorod
In nanotechnology, nanorods are one morphology of nanoscale objects. Each of their dimensions range from 1–100 nm. They may be synthesized from metals or semiconducting materials. Standard aspect ratios (length divided by width) are 3-5. Nanorods are produced by direct chemical synthesis. A combination of ligands act as shape control agents and bond to different facets of the nanorod with different strengths. This allows different faces of the nanorod to grow at different rates, producing an elongated object. One potential application of nanorods is in display technologies, because the reflectivity of the rods can be changed by changing their orientation with an applied electric field. Another application is for microelectromechanical systems (MEMS). Nanorods, along with other noble metal nanoparticles, also function as theragnostic agents. Nanorods absorb in the near IR, and generate heat when excited with IR light. This property has led to the use of nanorods as canc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanoring
A nanoring is a cyclic nanostructure with a thickness small enough to be on the nanoscale (10−9 meters). Note that this definition allows the diameter of the ring to be larger than the nanoscale. Overview and history The first nanorings were made of gallium nitride in 2001. Nanorings have been prepared from zinc oxide and cyclo-para-phenylenes as well as porphyrins. Although nanorings may have a diameter on the nanoscale, many of these materials have diameters that are larger than 100 nm, with many nanorings having a diameter on the microscale (10−6 meters). As such, nanorings are considered to be members of a sub-class of nanomaterials called one-dimensional (1-D) nanomaterials. These are nanomaterials in which one of the three physical dimensions in a single unit of the material is on a length scale greater than the nanoscale. Other examples of one-dimensional nanomaterials are nanowires, nanobelts, nanotubes, and nanosheets. Mechanical As with other nanomaterials, na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
