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Polyphenols (/ ˌpɒliˈfiːnoʊl, - nɒl /) are a large family of naturally occurring phenols. [ 1 ] They are abundant in plants and structurally diverse. [ 1 ][ 2 ][ 3 ] Polyphenols include phenolic acids, flavonoids, tannic acid, and ellagitannin, some of which have been used historically as dyes and for tanning garments.
Microwave chemistry is the science of applying microwave radiation to chemical reactions. [1][2][3][4][5] Microwaves act as high frequency electric fields and will generally heat any material containing mobile electric charges, such as polar molecules in a solvent or conducting ions in a solid. Polar solvents are heated as their component ...
Microwave digestion is a chemical technique used to decompose sample material into a solution suitable for quantitative elemental analysis via inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectroscopy, or atomic emission spectroscopy (including ICP-AES). It is commonly used in analyses for heavy metals.
The coupling coefficient of resonators is a dimensionless value that characterizes interaction of two resonators. Coupling coefficients are used in resonator filter theory. Resonators may be both electromagnetic and acoustic. Coupling coefficients together with resonant frequencies and external quality factors of resonators are the generalized ...
For other uses, see Microwaves (disambiguation). A telecommunications tower with a variety of dish antennas for microwave relay links on Frazier Peak, Ventura County, California. The apertures of the dishes are covered by plastic sheets (radomes) to keep out moisture. Microwave is a form of electromagnetic radiation with wavelengths shorter ...
Carrots, squash, broccoli, sweet potatoes, tomatoes (which gain their color from the compound lycopene), kale, mangoes, oranges, seabuckthorn berries, wolfberries (goji), collards, cantaloupe, peaches and apricots are particularly rich sources of beta-carotene, the major provitamin A carotenoid. Vitamin C (ascorbic acid) is a water- soluble ...
Accelerated solvent extraction. Accelerated solvent extraction (ASE), also known as pressurized solvent extraction (PSE), is a method for extracting various chemicals from a complex solid or semisolid sample matrix. The process uses high temperature and pressure, which results in the extraction taking less time and requiring less solvent, and ...
At bottom are the vacuum pumps. A hydrogen radio frequency discharge, the first element inside a hydrogen maser (see description below) A maser is a device that produces coherent electromagnetic waves (microwaves), through amplification by stimulated emission. The term is an acronym for microwave amplification by stimulated emission of radiation.