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Electrization of Liquids
Published in Dmitry A. Biryukov, Denis N. Gerasimov, Eugeny I. Yutin, Cavitation and Associated Phenomena, 2021
Dmitry A. Biryukov, Denis N. Gerasimov, Eugeny I. Yutin
The resolution of a spectrometer is usually described by the parameter FWHM—full width at half maximum (see Fig. 8.5.1). For a spectrometer, regardless of its construction, its signal always ‘diffuses’ on the wavelengths, more or less. Even a monochromatic signal at a certain wavelength λ0 is perceived by a spectrometer as the ‘hill’ shown in Fig. 8.5.1; the measure of width for this hill is FWHM. To draw the form of the line one must know the function f(λ) corresponding to the given spectrometer; usually this is a thing-in-itself and is not provided by the manufacturers of the spectrometer who usually present only an estimation of the FWHM parameter. In many cases, the Gaussian can be used for such a function: I(λ)=I02πσ2exp(−(λ−λ0)2σ2).
Electro-optic and Opto-electronic Devices
Published in David R. Goff, Kimberly Hansen, Michelle K. Stull, Fiber Optic Video Transmission, 2013
David R. Goff, Kimberly Hansen, Michelle K. Stull
Figure 7.1 (next page) illustrates the spectral characteristics of LEDs and lasers, given in FWHM. FWHM stands for full width half maximum, a measure of the width of the optical spectrum taken at the point where the intensity falls to half of the maximum value. An 850 nm surface-emitting LED has a FWHM of 60 nm, which usually dramatically limits the achievable bandwidth of such devices because of the high dispersion of the fiber 850 nm. A surface-emitting 1310 nm LED has an even wider spectrum with a typical FWHM of single-mode SM fiber since the fiber dispersion is zero near 1310 nm. This wider spectrum causes increased dispersion and also poses difficulties in WDM systems. A 1550 nm surface-emitting LED would even be wider. An edge-emitting 1310 nm LED has a more compact spectrum with a typical FWHM of about 50 nm.
Light Emitters
Published in David R. Goff, Kimberly Hansen, Michelle K. Stull, Fiber Optic Reference Guide, 2002
David R. Goff, Kimberly Hansen, Michelle K. Stull
An 850 nm surface-emitting LED has a FWHM of 60 nm. FWHM stands for full width half maximum, a measure of the width of the optical spectrum taken at the point where the intensity falls to half of the maximum value. A surface-emitting 1300 nm LED has an even wider spectrum with a typical FWHM of 110 nm. This wider spectrum causes increased dispersion and also poses difficulties in WDM systems. A 1550 nm surface-emitting LED would even be wider. The last figure shows an edge-emitting 1300 nm LED. It has a much more compact spectrum with a typical FWHM of about 50 nm.
Investigation and Analysis of Thermoelectrically Cooled CZT Performance
Published in Nuclear Technology, 2023
Amanda D. E. Foley, Swomitra K. Mohanty, Glenn E. Sjoden
The details regarding the FWHM and detector resolution are covered in great detail in many radiation detection texts.1,10 To summarize for completeness and to enable specific discussions relevant to this work, the peak FWHM is calculated by determining the peak centroid channel containing the maximum counts in the photo peak. The counts in the centroid channel are then divided by two to determine the half maximum. The FWHM is the span of channels between the channels corresponding to the half-maximum counts. The resolution is the FWHM divided by the centroid channel. The centroid channel shifts as temperature changes. Utilizing the resolution in terms of energy is impractical in this case. Therefore, the resolution is expressed as a percent and entirely based on channel number. Resolution in terms of energy is applicable only when an accurate energy calibration is available. The resolution in terms of percent is the resolution multiplied by 100. The resolution in terms of energy is the resolution multiplied by the energy calibration slope. Figure 2 depicts the FWHM, and Eq. (1) is the resolution R using the variables defined in Fig. 2:
Effects of variations in the tragus expansion angle on physical comfort for in-ear wearables
Published in Ergonomics, 2022
Mengcheng Wang, Hao Fan, Suihuai Yu, Xiao Zhao, Long Wang, Wenhua Li, Lei Wang, Mingjiu Yu, Jianjie Chu, Shuai Zhang, Dengkai Chen
Statistical analysis was conducted at α = 0.05 with Matlab R2018a, and p < 0.05 was considered statistically significant. The independent-samples t-test was performed to examine the differences between genders in the TEI of each ATMC prototype. The paired-samples t-test was conducted to examine the differences between both ears in terms of the ratings and corresponding TEI values. Gaussian peak function (GaussAmp) was employed to explore the (dis)comfort rating model of the TEI (Equations 3, 4). where is the offset, is the centre, is the width, and is the amplitude. FWHM means full width at half maximum.
Investigation of Al-doped CuO thin film deposition by the thermionic vacuum arc technique
Published in Transactions of the IMF, 2021
Suat Pat, Reza Mohammadigharehbagh, Caner Musaoglu, Soner Özen, Şadan Korkmaz
The crystallite size (D) of the deposited thin film was estimated by the following Scherrer’s equation.20,21where λ is the X-ray wavelength used (equal to 0.15406 nm) and θ is the diffraction angle. The minimum and maximum values of crystallite size are 11 and 28 nm, respectively, for the deposited thin film in different planes. FWHM is the full width at half of the maximum intensity of the related peak.