Investigation of the characteristics and increase in the accuracy of a pulsed meter for measuring the coordinates of the energy center of the transverse cross section of a laser beam

1988 ◽  
Vol 31 (2) ◽  
pp. 128-131
Author(s):  
V. A. Shangin ◽  
I. I. Shangina
Keyword(s):  
Laser Beam ◽  
Cross Section ◽  
Transverse Cross Section ◽  
Energy Center

scholarly journals Sources of Variability in the Response of Labeled Microspheres and B Cells during the Analysis by a Flow Cytometer

2021 ◽  
Vol 22 (15) ◽  
pp. 8256
Author(s):  
Adolfas K. Gaigalas ◽  
Yu-Zhong Zhang ◽  
Linhua Tian ◽  
Lili Wang
Keyword(s):  
B Cells ◽  
Laser Beam ◽  
Cross Section ◽  
Mean Fluorescence Intensity ◽  
Numerical Aperture ◽  
Flow Cytometer ◽  
Fluorescence Signal ◽  
Minor Importance ◽  
Reliable Measure ◽  
The Mean

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.

Adaptation of Cardinal Points Symmetry Landmarks Distribution Model to in-vivo B-Mode Ultrasound Images of Transverse Cross-section of Carotid Arteries

2021 ◽  
Vol 6 (7) ◽  
pp. 107-113
Author(s):  
Charles Nnamdi Udekwe ◽  
Akinlolu Adediran Ponnle
Keyword(s):  
Carotid Artery ◽  
Cross Section ◽  
Carotid Arteries ◽  
Region Of Interest ◽  
Transverse Cross Section ◽  
Transverse Plane ◽  
Distribution Model ◽  
Ultrasound Images ◽  
Symmetry Line

The geometry of the imaged transverse cross-section of carotid arteries in in-vivo B-mode ultrasound images are most times irregular, unsymmetrical, full of speckles and usually non-uniform. We had earlier developed a technique of cardinal point symmetry landmark distribution model (CPS-LDM) to completely characterize the Region of Interest (ROI) of the geometric shape of thick-walled simulated B-mode ultrasound images of carotid artery imaged in the transverse plane, but this was based on the symmetric property of the image. In this paper, this developed technique was applied to completely characterize the region of interest of the geometric shape of in-vivo B-mode ultrasound images of non-uniform carotid artery imaged in the transverse plane. In order to adapt the CPS-LD Model to the in-vivo carotid artery images, the single VS-VS vertical symmetry line common to the four ROIs of the symmetric image is replaced with each ROI having its own VS-VS vertical symmetry line. This adjustment enables the in-vivo carotid artery images possess symmetric properties, hence, ensuring that all mathematical operations of the CPS-LD Model are conveniently applied to them. This adaptability was observed to work well in segmenting the in-vivo carotid artery images. This paper shows the adaptive ability of the developed CPS-LD Model to successfully annotate and segment in-vivo B-mode ultrasound images of carotid arteries in the transverse cross-sectional plane either they are symmetrical or unsymmetrical.

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

2018 ◽  
Vol 9 (1) ◽  
pp. 56-65 ◽  
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 %. 

Formation of given field distribution in laser-beam cross section

1984 ◽  
Vol 27 (5) ◽  
pp. 411-413
Author(s):  
V. B. Korshikov ◽  
P. R. Lakhno ◽  
V. N. Rozhdestvin
Keyword(s):  
Laser Beam ◽  
Cross Section ◽  
Field Distribution ◽  
Beam Cross Section

Curvature and Out-of-Plane-Strain for Generalized Plane Strain

1972 ◽  
Vol 39 (3) ◽  
pp. 827-829 ◽  
Author(s):  
V. J. Parks
Keyword(s):  
Plane Strain ◽  
Cross Section ◽  
Central Region ◽  
Transverse Cross Section ◽  
Infinite Length ◽  
Out Of Plane ◽  
Plane Solution ◽  
Generalized Plane Strain

Out-of-plane strains and stresses are determined using reciprocity for the central region of very long bars (approaching infinite length) of uniform transverse cross section subjected to the same in-plane loads on every cross section. The loading explicitly specifies no end loads on the bars. The results are obtained without recourse to the in-plane solution. Conversely the end force and moment are determined for the case where the out-of-plane strain is zero.

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