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Gain Factor (gain + factor)

Distribution by Scientific Domains

Chemistry	57%
Engineering	42%

Selected Abstracts

Gain factor of horn array feed offset parabolic cylindrical reflector antenna for spatial power combining

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2010
Z. M. Xie
Abstract A study on the horn array feeding offset parabolic cylindrical reflector antenna for spatial power combining is presented. The calculations based on the aperture integral method are agreed well with the measurements. The relationship between the gain factor and the dimensions of the antenna is analyzed. The optimal dimensions and orientation of the feeding horn as well as the optimal spread angle of the reflector are given. It is revealed that the gain factor of the antenna with an E_plane array feed is higher than that of the antenna with an H_plane array feed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1742,1747, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25348 [source]

Performance of a confocal multilayer X-ray optic

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2002
J. Kusz
In recent years, several companies have developed the technique of arranging two multilayer mirrors in confocal optics for monochromatizing X-rays. In this study, a focusing device of Osmic Inc., with a source-to-focus distance of 1005,mm, has been used. The goal was to measure the homogeneity of the beam, the cross section at various distances from the focus and the efficiency of the optic when it is operated with vacuum and with air in the beam path. A small crystal sphere set at various distances is used to compare the intensities and the widths of reflections with those of a flat graphite monochromator. In a standard diffraction experiment (crystal size 0.25,mm), the gain factor with respect to graphite is roughly ten at a position where the beam plateau is 0.5,mm. The suppression of the Cu K, radiation and of higher harmonics of K, is very good. [source]

Weighting hyperspectral image data for improved multivariate curve resolution results

JOURNAL OF CHEMOMETRICS, Issue 9 2008
Howland D. T. Jones
Abstract The combination of hyperspectral confocal fluorescence microscopy and multivariate curve resolution (MCR) provides an ideal system for improved quantitative imaging when multiple fluorophores are present. However, the presence of multiple noise sources limits the ability of MCR to accurately extract pure-component spectra when there is high spectral and/or spatial overlap between multiple fluorophores. Previously, MCR results were improved by weighting the spectral images for Poisson-distributed noise, but additional noise sources are often present. We have identified and quantified all the major noise sources in hyperspectral fluorescence images. Two primary noise sources were found: Poisson-distributed noise and detector-read noise. We present methods to quantify detector-read noise variance and to empirically determine the electron multiplying CCD (EMCCD) gain factor required to compute the Poisson noise variance. We have found that properly weighting spectral image data to account for both noise sources improved MCR accuracy. In this paper, we demonstrate three weighting schemes applied to a real hyperspectral corn leaf image and to simulated data based upon this same image. MCR applied to both real and simulated hyperspectral images weighted to compensate for the two major noise sources greatly improved the extracted pure emission spectra and their concentrations relative to MCR with either unweighted or Poisson-only weighted data. Thus, properly identifying and accounting for the major noise sources in hyperspectral images can serve to improve the MCR results. These methods are very general and can be applied to the multivariate analysis of spectral images whenever CCD or EMCCD detectors are used. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Gain factor of horn array feed offset parabolic cylindrical reflector antenna for spatial power combining

Impedance Losses in Negative Capacitance Circuits for Semi-Passive Vibration Control with Piezo-Ceramics

PROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2006
Robert Oleskiewicz
Damping or absorbing effect in vibration control applications with piezo elements may be customized by an external impedance shunt branch connected to the plates of the piezo element. The negative capacitance present in the shunt significantly improves the damping and absorbing performance of such systems. The circuit is built up of an electronic gyrator realized by the operational amplifier, which is in reality not the ideal element. Therefore the performance of the proposed systems is limited, concerning the maximum voltages and currents at which the operational amplifiers can operate. In the paper, the finite gain of the operational amplifier, together with the loss impedances and the feedback gain factor is studied. The influence of the certain imperfections in the design of the electronic gyrator is based on 1DOF mechanical oscillator, with a piezo stack. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Polycapillary-optics-based micro-XANES and micro-EXAFS at a third-generation bending-magnet beamline

JOURNAL OF SYNCHROTRON RADIATION, Issue 2 2009
Geert Silversmit
A focusing system based on a polycapillary half-lens optic has been successfully tested for transmission and fluorescence µ-X-ray absorption spectroscopy at a third-generation bending-magnet beamline equipped with a non-fixed-exit Si(111) monochromator. The vertical positional variations of the X-ray beam owing to the use of a non-fixed-exit monochromator were shown to pose only a limited problem by using the polycapillary optic. The expected height variation for an EXAFS scan around the Fe K -edge is approximately 200,µm on the lens input side and this was reduced to ,1,µm for the focused beam. Beam sizes (FWHM) of 12,16,µm, transmission efficiencies of 25,45% and intensity gain factors, compared with the non-focused beam, of about 2000 were obtained in the 7,14,keV energy range for an incoming beam of 0.5 × 2,mm (vertical × horizontal). As a practical application, an As K -edge µ-XANES study of cucumber root and hypocotyl was performed to determine the As oxidation state in the different plant parts and to identify a possible metabolic conversion by the plant. [source]

A quantitative network model for color categorization,

COLOR RESEARCH & APPLICATION, Issue 4 2002
K. Okajima
Abstract To clarify the higher-order mechanism of human color perception, we measured the color appearances of 78 colored lights by an elemental color-scaling method and by a categorical color naming method. The colors covered nearly the entire CIE 1931 xy -chromaticity diagram with three different surrounds. The results showed that firm basic color zones derived by categorical color naming can be mapped with no overlap in an opponent-color response space. We propose a network model with a threshold selector, maximum selectors, and multiplication units with gain factors to generate the categorical color responses quantitatively from the elemental color responses. The model can predict the categorical color naming results in different surround conditions with no change of parameters. This suggests that a nonlinear color vision mechanism for color categorization exists between the primary visual cortex (V1) and the inferior temporal cortex (IT) in the human brain. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 225,232, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10060 [source]