| absorption spectroscopy | <investigation> This is the use of a spectrophotometer to measure the ability of particles (solutes) in a solution to absorb light through a range of specific wavelengths. Every compound absorbs light differently, so absorption spectra can be used to identify compounds, measure concentrations, and determine reaction rates. (15 Jan 1998) |
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| atomic absorption spectrophotometry | Determination of concentration by the ability of atoms to absorb radiant energy of specific wavelengths. (05 Mar 2000) |
| spectrophotometry, atomic absorption | A highly sensitive technique used to analyze various elements, especially metals, including aluminum, arsenic, beryllium, calcium, copper, iron, lead, and lithium, which are present in trace amounts. The atoms are excited above a ground state by flame vaporization, and the radiation emitted as the molecules return to a ground state is measured in unexcited non-ionised molecules. (12 Dec 1998) |
| magnetic resonance spectroscopy | Detection and measurement of the resonant spectra of molecular species in a tissue or sample. (05 Mar 2000) |
| Parallel Electron Energy Loss Spectroscopy | <technique> Electron energy loss spectroscopy analyses the inelastically scattered electrons present in the beam after it has been transmitted through the sample. An electron energy loss spectrum typically consists of a monatomic decreasing background on which are superimposed a number of peaks. Each peak is characteristic of the scattering process that has occurred in the sample. The peaks can be used to obtain information about the chemical composition and electronic structure of the sample. Electron energy loss spectra are acquired typically in a magnetic sector spectrometer located under the camera chamber of the transmission electron microscope. Spatial resolution is typically limited by the minimum probe diameter of the microscope. Electron energy loss spectroscopy tends to be complimentary to EDS in that it can be used to analyse very thin samples of low Z materials. Acronym: PEELS (05 Aug 1998) |
| clinical spectroscopy | Spectroscopic examination of specimens of living tissue, including fluids removed therefrom. Synonym: clinical spectroscopy. Origin: bio-+ L. Spectrum, image, + G. Skopeo, to examine (05 Mar 2000) |
| spectroscopy | <procedure> Spectroscopy is the science of measuring the emission and absorption of different wavelengths (spectra) of visible and non-visible light, this can be done via a spectroscope, which consists of a slit, prism, collimator lens, object lens, and a grating. (09 Oct 1997) |
| spectroscopy, fourier transform infrared | A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained. (12 Dec 1998) |
| spectroscopy, mossbauer | A spectroscopic technique which uses the mossbauer effect (inelastic scattering of gamma radiation resulting from interaction with heavy nuclei) to monitor the small variations in the interaction between an atomic nucleus and its environment. Such variations may be induced by changes in temperature, pressure, chemical state, molecular conformation, molecular interaction, or physical site. It is particularly useful for studies of structure-activity relationship in metalloproteins, mobility of heavy metals, and the state of whole tissue and cell membranes. (12 Dec 1998) |
| spectroscopy, near-infrared | A noninvasive technique that uses the differential absorption properties of haemoglobin and myoglobin to evaluate tissue oxygenation and indirectly can measure regional haemodynamics and blood flow. Near-infrared light (nir) can propagate through tissues and at particular wavelengths is differentially absorbed by oxgenated vs. Deoxygenated forms of haemoglobin and myoglobin. Illumination of intact tissue with nir allows qualitative assessment of changes in the tissue concentration of these molecules. The analysis is also used to determine body composition. (12 Dec 1998) |
| infrared spectroscopy | The study of the specific absorption in the infrared region of the electromagnetic spectrum; used in the study of the chemical bonds within molecules. (05 Mar 2000) |
| electron spin resonance spectroscopy | <radiology> A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. electron nuclear double resonance (endor) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications. (12 Dec 1998) |
| Energy Dispersive Spectroscopy | <technique> A microanalytical technique that is based on the characteristic X-ray peaks that are generated when the high energy beam of the electron microscope interacts with the specimen. Each element yields a characteristic spectral fingerprint that may be used to identify the presence of that element within the sample. The relative intensities of the spectral peaks may be used to determine the relative concentrations of each element in the specimen. The X-ray signal is detected by a solid-state silicon-lithium detector and the construction and efficiency of this detector sets a lower limit on the atomic number that may be detected. Generally elements heavier than carbon (Z=5) are detectable. Acronym: EDS (05 Aug 1998) |
| atomic | 1. Of or pertaining to atoms. 2. Extremely minute; tiny. Atomic philosophy, or Doctrine of atoms, a system which assuming that atoms are endued with gravity and motion accounted thus for the origin and formation of all things. This philosophy was first broached by Leucippus, was developed by Democritus, and afterward improved by Epicurus, and hence is sometimes denominated the Epicurean philosophy. <chemistry> Atomic theory, or the Doctrine of definite proportions, the weight of the atom of an element as compared with the weight of the atom of hydrogen, taken as a standard. Origin: Cf. F. Atomique. Source: Websters Dictionary (01 Mar 1998) |
| atomic bomb | <physics, radiobiology> A weapon with a large explosive power due to the sudden release of energy when the nuclei of heavy atoms such as plutonium-239 or uranium-235 are split. This fission is brought about by the bombardment of the fuel with neutrons, setting off a chain reaction. The bomb releases shock, blast, heat, light, and lethal radiation. The world's first atomic bomb was successfully tested by the United States on July 16, 1945. (13 Nov 1997) |