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Plasmonic Nanoparticles
Plasmonic nanoparticles are particles whose electron density can Coupling (physics), couple with electromagnetic radiation of wavelengths that are far larger than the particle due to the nature of the dielectric-metal interface between the medium and the particles: unlike in a pure metal where there is a maximum limit on what size wavelength can be effectively coupled based on the material size. What differentiates these particles from normal surface plasmons is that plasmonic nanoparticles also exhibit interesting scattering, absorbance, and Plasmon Coupling, coupling properties based on their geometries and relative positions. These unique properties have made them a focus of research in many applications including solar cells, spectroscopy, signal enhancement for imaging, and cancer treatment. Their high sensitivity also identifies them as good candidates for designing mechano-optical instrumentation. Plasmons are the oscillations of free electrons that are the consequence of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Evolution Of A Plane-wave Pulse Interacting With The Nanoparticles (lateral)
Time is the continued sequence of existence and event (philosophy), events that occurs in an apparently irreversible process, irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantification (science), quantify derivative, rates of change of physical quantity, quantities in scientific realism, material reality or in the consciousness, conscious qualia, experience. Time is often referred to as a fourth dimension, along with Three-dimensional space, three spatial dimensions. Time has long been an important subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circular definition, circularity has consistently eluded scholars. Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Equation
In mathematics, a differential equation is an equation that relates one or more unknown functions and their derivatives. In applications, the functions generally represent physical quantities, the derivatives represent their rates of change, and the differential equation defines a relationship between the two. Such relations are common; therefore, differential equations play a prominent role in many disciplines including engineering, physics, economics, and biology. Mainly the study of differential equations consists of the study of their solutions (the set of functions that satisfy each equation), and of the properties of their solutions. Only the simplest differential equations are solvable by explicit formulas; however, many properties of solutions of a given differential equation may be determined without computing them exactly. Often when a closed-form expression for the solutions is not available, solutions may be approximated numerically using computers. The theory of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold Nanorods
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 can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Membrane
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of cells and organelles, being selectively permeable to ions a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidermal Growth Factor Receptor
The epidermal growth factor receptor (EGFR; ErbB-1; HER1 in humans) is a transmembrane protein that is a receptor for members of the epidermal growth factor family (EGF family) of extracellular protein ligands. The epidermal growth factor receptor is a member of the ErbB family of receptors, a subfamily of four closely related receptor tyrosine kinases: EGFR (ErbB-1), HER2/neu (ErbB-2), Her 3 (ErbB-3) and Her 4 (ErbB-4). In many cancer types, mutations affecting EGFR expression or activity could result in cancer. Epidermal growth factor and its receptor was discovered by Stanley Cohen of Vanderbilt University. Cohen shared the 1986 Nobel Prize in Medicine with Rita Levi-Montalcini for their discovery of growth factors. Deficient signaling of the EGFR and other receptor tyrosine kinases in humans is associated with diseases such as Alzheimer's, while over-expression is associated with the development of a wide variety of tumors. Interruption of EGFR signalling, either by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectroscopy
Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter waves and acoustic waves can also be considered forms of radiative energy, and recently gravitational waves have been associated with a spectral signature in the context of the Laser Interferometer Gravitational-Wave Observatory (LIGO) In simpler terms, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Historically, spectroscopy originated as the study of the wavelength dependence of the absorption by gas phase matter of visible light dispersed by a prism. Spectroscopy, primarily in the electromagnetic spectrum, is a fundamental exploratory tool in the fields of astronomy, chemistry, materials science, and physics, allowing the composition, physical structure and e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoexcitation
Photoexcitation is the production of an excited state of a quantum system by photon absorption. The excited state originates from the interaction between a photon and the quantum system. Photons carry energy that is determined by the wavelengths of the light that carries the photons. Objects that emit light with longer wavelengths, emit photons carrying less energy. In contrast to that, light with shorter wavelengths emit photons with more energy. When the photon interacts with a quantum system, it is therefore important to know what wavelength one is dealing with. A shorter wavelength will transfer more energy to the quantum system than longer wavelengths. On the atomic and molecular scale photoexcitation is the photoelectrochemical process of electron excitation by photon absorption, when the energy of the photon is too low to cause photoionization. The absorption of the photon takes place in accordance with Planck's quantum theory. Photoexcitation plays a role in photoisomeri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanolithography
Nanolithography (NL) is a growing field of techniques within nanotechnology dealing with the engineering (patterning e.g. etching, depositing, writing, printing etc) of nanometer-scale structures on various materials. The modern term reflects on a design of structures built in range of 10−9 to 10−6 meters, i.e. nanometer scale. Essentially, the field is a derivative of lithography, only covering very small structures. All NL methods can be categorized into four groups: photo lithography, scanning lithography, soft lithography and other miscellaneous techniques. History The NL has evolved from the need to increase the number of sub-micrometer features (e.g. transistors, capacitors etc.) in an integrated circuit in order to keep up with Moore's Law. While lithographic techniques have been around since the late 18th century, none were applied to nanoscale structures until the mid-1950s. With evolution of the semiconductor industry, demand for techniques capable of producing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferroelectric
Ferroelectricity is a characteristic of certain materials that have a spontaneous electric polarization that can be reversed by the application of an external electric field. All ferroelectrics are also piezoelectric and pyroelectric, with the additional property that their natural electrical polarization is reversible. The term is used in analogy to ferromagnetism, in which a material exhibits a permanent magnetic moment. Ferromagnetism was already known when ferroelectricity was discovered in 1920 in Rochelle salt by Joseph Valasek.See and Thus, the prefix ''ferro'', meaning iron, was used to describe the property despite the fact that most ferroelectric materials do not contain iron. Materials that are both ferroelectric ''and'' ferromagnetic are known as multiferroics. Polarization When most materials are electrically polarized, the polarization induced, ''P'', is almost exactly proportional to the applied external electric field ''E''; so the polarization is a linear fun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porphin
Porphine or porphin is an organic chemical compound with formula . The molecule, which is flat, consists of four pyrrole-like rings joined by four methine (= C H−) groups to form a larger macrocycle ring, which makes it the simplest of the tetrapyrroles. It is classified as an aromatic and heterocyclic compound. Porphine is only of theoretical interest. It has been detected in GC-MS of certain fractions of ''Piper betle''. Porphine derivatives: porphyrins Substituted derivatives of porphine are called porphyrins. Many porphyrins are found in nature with the dominant example being protoporphyrin IX. Many synthetic porphyrins are also known, including octaethylporphyrin and tetraphenylporphyrin. File:PPIXtransH.png, Derivatives of protoporphyrin IX are common in nature, the precursor to hemes. File:H2octaethylporphyrin.png , Octaethylporphyrin (H2OEP) is a synthetic analogue of protoporphyrin IX. Unlike the natural porphyrin ligands, OEP2− is highly symmetrical. File ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot-carrier Injection
Hot carrier injection (HCI) is a phenomenon in solid-state electronic devices where an electron or a “hole” gains sufficient kinetic energy to overcome a potential barrier necessary to break an interface state. The term "hot" refers to the effective temperature used to model carrier density, not to the overall temperature of the device. Since the charge carriers can become trapped in the gate dielectric of a MOS transistor, the switching characteristics of the transistor can be permanently changed. Hot-carrier injection is one of the mechanisms that adversely affects the reliability of semiconductors of solid-state devices. Physics The term “hot carrier injection” usually refers to the effect in MOSFETs, where a carrier is injected from the conducting channel in the silicon substrate to the gate dielectric, which usually is made of silicon dioxide (SiO2). To become “hot” and enter the conduction band of SiO2, an electron must gain a kinetic energy of ~3.2&n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photovoltaic
Photovoltaics (PV) is the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. The photovoltaic effect is commercially used for electricity generation and as photosensors. A photovoltaic system employs solar modules, each comprising a number of solar cells, which generate electrical power. PV installations may be ground-mounted, rooftop-mounted, wall-mounted or floating. The mount may be fixed or use a solar tracker to follow the sun across the sky. Photovoltaic technology helps to mitigate climate change because it emits much less carbon dioxide than fossil fuels. Solar PV has specific advantages as an energy source: once installed, its operation generates no pollution and no greenhouse gas emissions, it shows scalability in respect of power needs and silicon has large availability in the Earth's crust, although other materials required in PV system man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
