Formation of given field distribution in laser-beam cross section

A stochastic model of the flow cytometer measurement process was developed to assess the nature of the observed coefficient of variation (CV%) of the mean fluorescence intensity (MFI) from a population of labeled microspheres (beads). Several sources of variability were considered: the total number of labels on a bead, the path through the laser beam, the optical absorption cross-section, the quantum yield, the numerical aperture of the collection optics, and the photoelectron conversion efficiency of the photomultiplier (PMT) cathode. The variation in the number of labels on a bead had the largest effect on the CV% of the MFI of the bead population. The variation in the path of the bead through the laser beam was minimized using flat-top lasers. The variability in the average optical properties of the labels was of minor importance for beads with sufficiently large number of labels. The application of the bead results to the measured CV% of labeled B cells indicated that the measured CV% was a reliable measure of the variability of antibodies bound per cell. With some modifications, the model can be extended to multicolor flow cytometers and to the study of CV% from cells with low fluorescence signal.

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Optical resolution of beam cross-section measurements by means of synchrotron radiation

Nuclear Instruments and Methods in Physics Research ◽

10.1016/0167-5087(82)90663-9 ◽

1982 ◽

Vol 203 (1-3) ◽

pp. 483-493 ◽

Cited By ~ 31

Author(s):

A. Hofmann ◽

F. Méot

Keyword(s):

Synchrotron Radiation ◽

Cross Section ◽

Optical Resolution ◽

Beam Cross Section

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Fatigue Assessment of Concrete Members Strengthened by FRP Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.617.221 ◽

2014 ◽

Vol 617 ◽

pp. 221-224 ◽

Cited By ~ 1

Author(s):

Alena Čavojcová ◽

Martin Moravcik

Keyword(s):

Fatigue Damage ◽

Cross Section ◽

Theoretical Approach ◽

Material Properties ◽

Beam Cross Section ◽

European Standard ◽

Fatigue Assessment ◽

Concrete Members ◽

Damage Structure ◽

T Beam

Fatigue and fatigue damage leads to a change in material properties that can lead to the element failures. Generally, it is necessary to verify the influence of the fatigue effects on the concrete members according to European standard EC2, [1]. FRP materials have been possibly used for the fatigue damage structure rehabilitation. There we can apply the condition of the limit boundaries stress on concrete and limit force in FRP material theoretical approach. Fatigue assessment will be analyzed for T-beam cross section with reinforcement and strengthened FPR material in this paper.

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INFLUENCE OF LASER BEAM PROFILE ON LIGHT SCATTERING BY HUMAN SKIN DURING PHOTOMETRY BY ELLIPSOIDAL REFLECTORS

Devices and Methods of Measurements ◽

10.21122/2220-9506-2018-9-1-56-65 ◽

2018 ◽

Vol 9 (1) ◽

pp. 56-65 ◽

Cited By ~ 1

Author(s):

M. A. Bezuglyi ◽

N. V. Bezuglaya ◽

S. Kostuk

Keyword(s):

Monte Carlo Simulation ◽

Adipose Tissue ◽

Laser Beam ◽

Human Skin ◽

Cross Section ◽

Beam Profile ◽

Laser Beam Profile ◽

Reflected Light ◽

Section Profile ◽

Cross Section Profile

The correct accounting of laser emitter parameters for improvement of diagnostic authenticity of methods of optical biomedical diagnostic is important problem for applied biophotonic tasks. The purpose of the current research is estimation of influence of energy distribution profile in transversal section of laser beam on light scattering by human skin layers at photometry by ellipsoidal reflectors.Biomedical photometer with ellipsoidal reflectors for investigation of biological tissue specimens in transmitted and reflected light uses laser probing radiation with infinitely thin, Gauss-type and uniform cross-section profile. Distribution of beams with denoted profiles, which consist of 20 million photons with wavelength 632.8 nm, was modeled by using of Monte-Carlo simulation in human skin layers (corneous layer, epidermis, derma and adipose tissue) of various anatomic thickness and with ellipsoidal reflectors with focal parameter equal to 16.875 mm and eccentricity of 0.66.The modeling results represent that illuminance distribution in zones of photometric imaging is significantly influenced by the laser beam cross-section profile for various thickness of corneous layer and epidermis in transmitted and reflected light, and also derma in reflected light. Illuminance distribution for adipose tissue in reflected and transmitted light, and also derma in transmitted light, practically do not depend of laser beam profile for anatomic thicknesses, which are appropriate for human skin on various sections of body.There are represented results of modified Monte-Carlo simulation method for biomedical photometer with ellipsoidal reflectors during biometry of human skin layers. For highly scattered corneous layer and epidermis the illumination of middle and external rings of photometric images changes depending from the laser beam profile for more than 50 % in transmitted and 30 % in reflected light. For weakly scattering skin layers (derma and adipose layer) the influence of profile can be observed only for derma in reflected layer and is equal not more than 15 %.

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