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Diketopyrrolopyrrole Dye
Diketopyrrolopyrroles (DPPs) are organic dyes and pigments based on the heterocyclic dilactam 2,5-dihydropyrrolo ,4-''c''yrrole-1,4-dione, widely used in optoelectronics. DPPs were initially used as pigments in the painting industry (e.g. in automotive paints) due to their high resistance to photodegradation. More recently, DPP derivatives have been also investigated as promising fluorescent dyes for bioimaging applications, as well as components of materials for use in organic electronics. Structure DPP dyes are based on the bicyclic heterocyclic compound diketopyrrolopyrrole. 2,5-Dihydropyrrolo ,4-cyrrol-1,4-dion is a basic body of Diketopyrrolopyrrole dye. DPP pigments are an important class of high-performance pigments used in inks, paints and plastic. More recently their optical-electronic performance was discovered for photovoltaic applications and related uses. Optical properties DPP has high stability to heat but not very well to acid and base. The alkylation of am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pigments
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compounds. Pigments of prehistoric and historic value include ochre, charcoal, and lapis lazuli. Economic impact In 2006, around 7.4 million tons of inorganic, organic, and special pigments were marketed worldwide. Estimated at around US$14.86 billion in 2018 and will rise at over 4.9% CAGR from 2019 to 2026. The global demand for pigments was roughly US$20.5 billion in 2009. According to an April 2018 report by ''Bloomberg Businessweek'', the estimated value of the pigment industry globally is $30 billion. The value of titanium dioxide – used to enhance the white brightness of many products – was placed at $13.2 billion per year, while the color Ferrari red is valued at $300 million each year. Physical principles Lik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequence of database operations that satisfies the ACID properties (which can be perceived as a single logical operation on the data) is called a ''transaction''. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction. In 1983, Andreas Reuter and Theo Härder coined the acronym ''ACID'', building on earlier work by Jim Gray who named atomicity, consistency, and durability, but not isolation, when characterizing the transaction concept. These four properties are the major guarantees of the transaction paradigm, which has influenced many aspects of development in database systems. According to Gray and Reuter, the IBM Informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocyclic Compounds With 2 Rings
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of these heterocycles. Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes. More than half of known compounds are heterocycles. 59% of US FDA-approved drugs contain nitrogen heterocycles. Classification The study of heterocyclic chemistry focuses especially on unsaturated derivatives, and the preponderance of work and applications involves unstrained 5- and 6-membered rings. Included are pyridine, thiophene, pyrrole, and furan. Another large class of heterocycles refers to those fused to benzene rings. For example, the fused benzene derivatives of pyridine, thiophene, pyrrole, and furan are quinol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactams
A lactam is a cyclic amide, formally derived from an amino alkanoic acid. The term is a portmanteau of the words ''lactone'' + ''amide''. Nomenclature Greek prefixes in alphabetical order indicate ring size: * α-Lactam (3-atom rings) * β-Lactam (4-atom rings) * γ-Lactam (5-atom rings) * δ-Lactam (6-atom rings) * ε-Lactam (7-atom rings) This ring-size nomenclature stems from the fact that a hydrolyzed α-Lactam leads to an α-amino acid and a β-Lactam to a β-amino acid, ''etc''. Synthesis General synthetic methods exist for the organic synthesis of lactams. Beckmann rearrangement Lactams form by the acid-catalyzed rearrangement of oximes in the Beckmann rearrangement. Schmidt reaction Lactams form from cyclic ketones and hydrazoic acid in the Schmidt reaction. Cyclization of amino acids Lactams can be formed from cyclisation of amino acids via the coupling between an amine and a carboxylic acid within the same molecule. Lactamization is most efficient in this wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensor
A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon. In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends the information to other electronics, frequently a computer processor. Sensors are always used with other electronics. Sensors are used in everyday objects such as touch-sensitive elevator buttons (tactile sensor) and lamps which dim or brighten by touching the base, and in innumerable applications of which most people are never aware. With advances in micromachinery and easy-to-use microcontroller platforms, the uses of sensors have expanded beyond the traditional fields of temperature, pressure and flow measurement, for example into Attitude and heading reference system, MARG sensors. Analog sensors such as potentiometers and force-sensing resistors are still widely used. Their applications include manufacturing and machinery, airplane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OLED
An organic light-emitting diode (OLED or organic LED), also known as organic electroluminescent (organic EL) diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current. This organic layer is situated between two electrodes; typically, at least one of these electrodes is transparent. OLEDs are used to create digital displays in devices such as television screens, computer monitors, and portable systems such as smartphones and handheld game consoles. A major area of research is the development of white OLED devices for use in solid-state lighting applications. There are two main families of OLED: those based on small molecules and those employing polymers. Adding mobile ions to an OLED creates a light-emitting electrochemical cell (LEC) which has a slightly different mode of operation. An OLED display can be driven with a passive-matrix (PMOLED) or active-matrix (AMOLED) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiophene
Thiophene is a heterocyclic compound with the formula C4H4S. Consisting of a planar five-membered ring, it is aromatic as indicated by its extensive substitution reactions. It is a colorless liquid with a benzene-like odor. In most of its reactions, it resembles benzene. Compounds analogous to thiophene include furan (C4H4O), selenophene (C4H4Se) and pyrrole (C4H4NH), which each vary by the heteroatom in the ring. Isolation and occurrence Thiophene was discovered as a contaminant in benzene. It was observed that isatin (an indole) forms a blue dye if it is mixed with sulfuric acid and crude benzene. The formation of the blue indophenin had long been believed to be a reaction of benzene itself. Viktor Meyer was able to isolate thiophene as the actual substance responsible for this reaction. Thiophene and especially its derivatives occur in petroleum, sometimes in concentrations up to 1–3%. The thiophenic content of oil and coal is removed via the hydrodesulfurization (HDS) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The inverse of the wavelength is called the spatial frequency. Wavelength is commonly designated by the Greek letter ''lambda'' (λ). The term ''wavelength'' is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids. Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths. Wavelength depends on the medium (for example, vacuum, air, or water) that a wav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, than the absorbed radiation. A perceptible example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the electromagnetic spectrum (invisible to the human eye), while the emitted light is in the visible region; this gives the fluorescent substance a distinct color that can only be seen when the substance has been exposed to UV light. Fluorescent materials cease to glow nearly immediately when the radiation source stops, unlike phosphorescent materials, which continue to emit light for some time after. Fluorescence has many practical applications, including mineralogy, gemology, medicine, chemical sensors (fluorescence spectroscopy), fluorescent labelling, dyes, biological detectors, cosmic-ray detection, vacu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkylation
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecting alkylation. Alkyl groups can also be removed in a process known as dealkylation. Alkylating agents are often classified according to their nucleophilic or electrophilic character. In oil refining contexts, alkylation refers to a particular alkylation of isobutane with olefins. For upgrading of petroleum, alkylation produces a premium blending stock for gasoline. In medicine, alkylation of DNA is used in chemotherapy to damage the DNA of cancer cells. Alkylation is accomplished with the class of drugs called alkylating antineoplastic agents. Nucleophilic alkylating agents Nucleophilic alkylating agents deliver the equivalent of an alkyl anion ( carbanion). The formal "alkyl anion" attacks an electrophile, forming a new covalent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photovoltaics
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 m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactam
A lactam is a cyclic amide, formally derived from an amino alkanoic acid. The term is a portmanteau of the words ''lactone'' + ''amide''. Nomenclature Greek prefixes in alphabetical order indicate ring size: * α-Lactam (3-atom rings) * β-Lactam (4-atom rings) * γ-Lactam (5-atom rings) * δ-Lactam (6-atom rings) * ε-Lactam (7-atom rings) This ring-size nomenclature stems from the fact that a hydrolyzed α-Lactam leads to an α-amino acid and a β-Lactam to a β-amino acid, ''etc''. Synthesis General synthetic methods exist for the organic synthesis of lactams. Beckmann rearrangement Lactams form by the acid-catalyzed rearrangement of oximes in the Beckmann rearrangement. Schmidt reaction Lactams form from cyclic ketones and hydrazoic acid in the Schmidt reaction. Cyclization of amino acids Lactams can be formed from cyclisation of amino acids via the coupling between an amine and a carboxylic acid within the same molecule. Lactamization is most efficient in this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
