Coefficients absorption. Medical search. Frequent questions

In chemistry, the molar absorption coefficient or molar attenuation coefficient (ε) is a measurement of how strongly a chemical species absorbs, and thereby attenuates, light at a given wavelength. (wikipedia.org)
The SI unit of molar absorption coefficient is the square metre per mole (m2/mol), but in practice, quantities are usually expressed in terms of M−1⋅cm−1 or L⋅mol−1⋅cm−1 (the latter two units are both equal to 0.1 m2/mol). (wikipedia.org)
The molar absorption coefficient is also known as the molar extinction coefficient and molar absorptivity, but the use of these alternative terms has been discouraged by the IUPAC. (wikipedia.org)
The molar absorption coefficient is usually decadic. (wikipedia.org)
The composition of a mixture of N absorbing species can be found by measuring the absorbance at N wavelengths (the values of the molar absorption coefficient for each species at these wavelengths must also be known). (wikipedia.org)
The mass absorption coefficient is equal to the molar absorption coefficient divided by the molar mass of the absorbing species. (wikipedia.org)
εm = ε⁄M where εm = Mass absorption coefficient ε = Molar absorption coefficient M = Molar mass of the absorbing species In biochemistry, the molar absorption coefficient of a protein at 280 nm depends almost exclusively on the number of aromatic residues, particularly tryptophan, and can be predicted from the sequence of amino acids. (wikipedia.org)
Similarly, the molar absorption coefficient of nucleic acids at 260 nm can be predicted given the nucleotide sequence. (wikipedia.org)
If the molar absorption coefficient is known, it can be used to determine the concentration of a protein in solution. (wikipedia.org)

Thus, uncertainties in indexing absorption peaks to their respective pigments may occur during the determination of these pigment absorption coefficients. (nature.com)
Determination of sound absorption coefficient and impedance in impedance tubes. (acoustic-standards.co.uk)
Method for the Experimental Determination of the Bunsen Absorption Coefficient of Hydraulic Flui. (rwth-aachen.de)
Loudspeaker configuration in reverberation rooms for sound absorption measurement using room mode determination. (dtu.dk)
The accuracy depends on several parameters such as the choice of background correction method, the accuracy in determination of the effective attenuation coefficient and the thickness of the body and organs and on the determination of the gamma camera sensitivity. (lu.se)

Applying general plasma spectroscopy theory, typical true emission and absorption coefficient profiles were calculated. (dtic.mil)
Using Integrating Ring-Down Spectroscopy (ICRDS), we are able to directly measure the absorption coefficient of any highly scattering media even in the presence of larger scattering cross sections and small absorptions. (aps.org)
The present laboratory practical deals with laser-based absorption spectroscopy, which is a very powerful technique for detection and quantification of species concentrations. (lu.se)
While absorption spectroscopy can be used for liquid and solid phase analysis, it is arguably best suited for gas-phase analysis, as free gases are characterized by extremely sharp absorption lines, typically 100 - 10000 times sharper than those encountered in liquids and solids (as schematically illustrated in the figure on the front cover). (lu.se)
Gas in Scattering Media Absorption Spectroscopy (GASMAS) it is possible to probe gases contained in dense, highly scattering, media. (lu.se)
GASMAS is based on tunable diode laser absorption spectroscopy (TDLAS), and the spectrum is thus acquired sequentially by scanning the wavelength of the narrow-band diode laser across an absorption feature. (lu.se)
The basic principle of direct absorption spectroscopy is simple: light with a frequency close to a transition frequency of the atom or molecule of interest is sent through the sample and the intensity of the light transmitted through the sample is detected (see Fig. 1). (lu.se)
Fig. 1 Schematic setup for absorption spectroscopy using a narrowband laser . (lu.se)

Nikon MicroscopyU: Introduction to Fluorescent Proteins includes a table of molar attenuation coefficient of fluorescent proteins. (wikipedia.org)
Transmission-style experiments measure the attenuation coefficient by comparing the intensity of a light source before and after it passes through a desired medium. (aps.org)
For highly scattering media, the light lost through scattering contributes significantly towards the attenuation coefficient. (aps.org)
Methods which take the volume of the source organ into consideration are recommended The discrepancy in the determined organ activity varied between an underestimation of 26% and an overestimation of 16% in the MIRD phantom, depending on which organ was studied and on the correction method used To correct for absorption and scattering, an effective attenuation coefficient was used. (lu.se)
A theoretical analysis showed that a change in the effective attenuation coefficient of 0.01 cm(-1) resulted in a 15% change in the calculated activity. (lu.se)
The quantification is improved if the attenuation coefficient is determined by transmission measurements. (lu.se)

Image showing periodicity of x-ray mass absorption coefficients (Fe-Kα) for 5d chemical elements. (webelements.com)

The changes observed in the absorption by three seawater components (phytoplankton, detritus and chromophoric dissolved organic matter or CDOM) were analyzed in relation to changes in bio-optical regions and composition of the phytoplankton community (determined based on phytoplankton pigments). (scirp.org)
Among many efforts that have been made to obtain information on phytoplankton pigments from bio-optical properties, Gaussian curves decomposed from phytoplankton absorption spectrum have been used to represent the light absorption of different pigments. (mdpi.com)
However, to date, efforts to simultaneously retrieve the concentrations of individual photosynthetic pigments from remotely-sensed data have been restricted due to the overlap of absorption spectra of different pigments which can mask the contribution of individual pigments to the reflectance and/or transmittance spectrum. (nature.com)
Photosynthetic pigments at discrete depths, Particle and Soluble absorption rates at discrete depths. (ucar.edu)

A standardized method estimates the random incidence absorption coefficient of a material sample by placing the material in a reverberation chamber, conducting an acoustical measurement and comparing it to another measurement of the empty chamber. (rwth-aachen.de)
The utility model belongs to irrigation and water conservancy technical field, is related to a kind of flow measurement device, and in particular to one kind is used for Determine the device of plain river network irrigation pumping station water-electricity conversion coefficient. (google.com)
The purpose of this utility model be to provide it is a kind of it is easy to use, be not take up agricultural land, flow measurement precision is high is used for Determine the device of plain river network irrigation pumping station water-electricity conversion coefficient. (google.com)
For quantitative measurement of fat absorption, a 72-hour fecal fat collection is often performed and is considered the standard. (medscape.com)

which defines μ, the total linear absorption coefficient. (webelements.com)

Linear decadic (\(a\),\(K\)) and Napierian absorption coefficients (\(\alpha \)) are equal to the corresponding @A00028@ divided by the optical path length through the sample. (iupac.org)

An optically pumped laser gain medium is often made with a length which is about 2 to 3 absorption lengths at the pump wavelength, so that the pump absorption is sufficiently effective. (rp-photonics.com)
Reynolds' (1967) method for relating the mass absorption coefficient on the long wavelength side of a major element absorption edge to the intensity of the emission line of the element causing the absorption discontinuity is shown to be a special case of a more general relation. (geoscienceworld.org)
If the ratio of the mass absorption coefficient on the short wavelength side to that on the long wavelength side of a major element's absorption edge is plotted against the peak intensity of this element, the plots allow use of the general relation and permit simultaneous comparisons to be made to more than one standard. (geoscienceworld.org)
By analyzing these spectrums, we determined absorption coefficient of these microorganisms for selected wavelength. (comu.edu.tr)

NGC is characterized by an average Chla of 0.7 mg/m3 and the predominance of picophytoplankton, characterized by the dominance of zeaxanthin (marker pigment for cyanobacteria) and/or chlorophyll b (marker pigment for green algae), along with a co-dominium by CDOM and phytoplankton to light absorption. (scirp.org)
Results indicate that Case II waters can be very different when evaluating the individual contribution by phytoplankton, detritus and CDOM to total light absorption what has to be considered for the selection of bio-optical models for each specific region what can also help to a better definition of the related uncertainties. (scirp.org)
Light absorption by phytoplankton, non - algal particles (NAP) and chromophoric dissolved organic matter (CDOM) was investigated at 90 sites of a clear, deep artificial lake (Lake Qiandaohu) to study natural variability of absorption coefficients. (mdpi.com)

It is shown that the structure in the form of a metal core covered with a layer of another metal leads to splitting and the appearance of two maxima in the frequency dependence of the absorption coefficient. (edu.ua)
The influence of the dimensionality of the systems has been established by comparing the frequency dependences of the composite absorption coefficient based on bimetallic nanowires and nanoparticles. (edu.ua)
Many other applications are emerging, for example ultrahigh sensitivity gas/vapour monitoring and absorption-based optical frequency references. (mrs.org)
1) where () is the frequency-dependent absorption coefficient. (lu.se)
2) where ( ) is the frequency-dependent absorption cross section, whose SI unit is m2, but it is commonly given in the unit cm2. (lu.se)

The wavelengths chosen are usually the wavelengths of maximum absorption (absorbance maxima) for the individual species. (wikipedia.org)

Using these coefficient profiles, true intensity and transmission profiles were obtained. (dtic.mil)
After four absorption lengths, only ≈1.8% of the initial intensity is left. (rp-photonics.com)
In order to determine the absorption, which is related to the concentration of the atom/molecule under investigation, the transmitted intensity is compared to the incident light intensity. (lu.se)

One defines the absorption length as the inverse of the absorption coefficient. (rp-photonics.com)
Comparing inverse absorption coefficient methods to tr. (rwth-aachen.de)

In this paper we present a novel method for determining scattering (S) and absorption (K) coefficients from total transmittance and reflectance measurements by inversion of the Kubelka-Munk theory. (ups.edu.ec)

UGC is characterized by an average Chla of 1.78 mg/m3, the dominance of microphytoplankton (diatoms and dinoflagellates) and a stronger contribution of detritus to total light absorption. (scirp.org)
The term penetration depth is often used with the same meaning as absorption length , but it should be considered as a more general term because limited penetration into a material may not only result from light absorption, but also from reflection. (rp-photonics.com)
Beer-Lambert law states that there is a logarithmic dependence between the transmissivity of light through a substance and the product of the absorption coefficient of the substance and the distance the light travels through the material. (wikicalculator.com)
The addition of eumelanin, whose absorption in the near infrared region is significantly higher than porous silicon, should greatly enhance the light absorption capabilities of the empty porous silicon matrix, which are very low in the low energy side of the visible spectral range (from about 600 nm downwards). (springer.com)
By injecting narrowband laser light into a highly scattering and porous material, a gas absorption imprint is generated as the light passes through gas-filled pores. (lu.se)

The analytic expressions for the absorption coefficient (ACF) of a weak electromagnetic wave (EMW) by confined electrons in rectangular quantum wires (RQWs) in the presence of laser radiation modulated by amplitude are calculated by using the quantum kinetic equation for electrons with the electron-optical phonon scattering mechanism. (jpier.org)
Nguyen Thi Thanh Nhan and Dinh Quoc Vuong, "Negative Absorption Coefficient of a Weak Electromagnetic Wave Caused by Electrons Confined in Rectangular Quantum Wires in the Presence of Laser Radiation Modulated by Amplitude," Progress In Electromagnetics Research M , Vol. 38, 73-82, 2014. (jpier.org)
10. Nhan, N. T. T. and N. V. Nhan, "Calculation absorption coefficient of a weak electromagnetic wave by confined electrons in cylindrical quantum wires in the presence of laser radiation by using the quantum kinetic equation," Progress In Electromagnetics Research M , Vol. 34, 47-54, 2014. (jpier.org)
In this paper analyzes the electromagnetic radiation absorption by a composite based on bimetallic nanowires. (edu.ua)
wideBandAbsorptionEmission radiation absorption and emission coefficients for continuous phase. (openfoam.com)

Within this version (PROSPECT-5), the separation of Chls and Cars absorption coefficients was band-by-band derived based on a minimum distance fitting method using modeled and measured in vivo spectra 13 . (nature.com)

In the second of these, HC-PCF gas-cells are filled with acetylene at low pressure, yielding a cluster of narrow absorption peaks in the 1550 nm band. (mrs.org)

To establish our nonexistence theorem, we adopt the Pohozaev nonlinear capacity method, and consider the combined effects of absorption and dispersion terms. (mdpi.com)

Investigation of the Effect of Finite Spectral Slit Width on the Spatial Resolution of Emission and Absorption Coefficients in Inhomogeneous Sources of Cylindrical Symmetry. (dtic.mil)
A numerical method was developed to determine the effect of finite spectral slit width on spatial resolution of emission and absorption coefficients in an argon arc plasma in local thermodynamic equilibrium. (dtic.mil)
Using an Abel iteration technique, observed emission and absorption coefficients were calculated. (dtic.mil)
Flag for whether the absorption/emission is for a grey gas. (openfoam.com)
Return emission coefficient for dispersed phase. (openfoam.com)

However, with this method, the specific absorption coefficients of Chla and Chlb could not be separated in PROSPECT-5 11 . (nature.com)
This paper presents a method using a ray-tracing technique to determine absorption coefficients for underground mines. (cdc.gov)

Thus, a spectrum carrying high-resolution gas absorption imprints may be detected at in principle any point. (lu.se)

Data on the absorption coefficients of air in the temperature range from 6000*K to 18,000*K are presented, and continuous and discrete contributions to the absorption of air in thermo. (rand.org)

Then the optical absorption coefficients (OACs) and refractive index changes (RICs) are calculated through the scheme of the compact density-matrix formalism. (edpsciences.org)
An accurate knowledge of optical absorption coefficients for cells and their constituents is critical to the continued progression of biomedical procedures and modeling. (aps.org)

Absorption coefficient for continuous phase. (openfoam.com)

They are a wonderful solution for spaces that demand proper sound control without complete acoustic absorption and small rooms with high SPLs (Sound Pressure Levels). (standsandmounts.com)

Room sound absorption and absorption coefficients for common materials like plaster walls, brickwork, plywood panels and more. (engineeringtoolbox.com)
Auralex Acoustics 4 inch Pyramid StudioFoam Sound Absorption Panels 2x4 ft. (standsandmounts.com)

The mass absorption coefficient, μ/ρ, expressed in units of cm 2 g -1 , where ρ is the density of the material, is approximately independent of the physical state of the material. (webelements.com)
Before the arrival of HC-PCF, there was simply no practical way to do this at visible and near-infrared frequencies because no cladding material exists that has a refractive index less than unity (one has to move to other spectral regions for this to happen) and metals, which could perhaps be used to form a mirror around a hollow core, have extremely high absorption losses. (mrs.org)

Absorption corrections are available for film data. (diamond.ac.uk)

Absorption coefficients as a description of the boundary conditions for room acoustics simulations are usually very challenging to determine. (rwth-aachen.de)

These observed and true coefficients were compared to determine an error pattern. (dtic.mil)

Small intestinal permeability was assessed using the lactulose/rhamnose dual sugar absorption test and small intestinal epithelial injury using Intestinal Fatty-Acid Binding Protein (I-FABP). (bvsalud.org)

Mean absorption coefficients and reverberation times in typical rooms. (engineeringtoolbox.com)

Moreover, they display a quite unusual set of physicochemical properties such as broadband monotonic absorption in the ultraviolet-visible [ 18 ]. (springer.com)

Studiofoam Pyramid is one of the most popular sound-absorption materials on the market. (standsandmounts.com)

An extra bit of sound diffusion and less sound absorption than 2 inch StudioFoam Wedges, designed to yield a less dry-sounding space with a bit more "air. (standsandmounts.com)

[ 3 ] Larger doses of lidocaine are generally tolerated during tumescent anesthesia for liposuction, probably due to coadministration of epinephrine, the low concentration of lidocaine in tumescent solution, and poor systemic absorption from subcutaneous fat. (medscape.com)

A fat absorption test is usually the first one ordered because there are many disease processes that can result in fat malabsorption. (medscape.com)

and C1 and C2 are coefficients of aerosol resistance, using the blue band to correct for aerosol influences in the red band. (cdc.gov)

Anatomy27

Organisms9

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Chemicals and Drugs82

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Psychiatry and Psychology1

Phenomena and Processes60

Disciplines and Occupations10

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Molar absorption coefficient9

Determination5

Spectroscopy8

Attenuation6

Mass absorption coefficients1

Pigments4

Measurement4

Linear absorption1

Decadic1

Wavelength4

Phytoplankton3

Frequency5

Maxima1

Intensity3

Inverse2

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