Caustic surface produced by a simple lens considering a point source placed at arbitrary position along the optical axis

2020 ◽  
Author(s):  
Osvaldo Ponce-Hernández ◽  
Maximino Avendaño-Alejo ◽  
Luis Castañeda
Keyword(s):  
Point Source ◽  
Optical Axis ◽  
Caustic Surface ◽  
Arbitrary Position

Journal Bearings With Arbitrary Position of Source—II

1961 ◽  
Vol 83 (4) ◽  
pp. 572-578 ◽  
Author(s):  
J. V. Fedor
Keyword(s):  
Point Source ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Vertical Plane ◽  
Journal Bearings ◽  
Diameter Ratio ◽  
Source Parameter ◽  
Rapid Rise ◽  
Finite Form ◽  
Arbitrary Position

A complete oil film solution of Reynolds equation is found that takes into account the presence of a point source. The solution gives integrated journal bearing characteristics in finite form. With the load in a vertical plane and the source at the top or bottom of the bearing, two simple universal relationships have emerged between the angle indicating the line of centers (α) and the eccentricity (b). With the source at the base of the bearing and −cos α = b, the plot of coefficient of friction versus the Sommerfeld variable goes through the origin and is essentially independent of bearing length to diameter ratio. Also, lubricant end flow becomes vanishingly small as the Sommerfeld variable approaches zero. With the source at the top of the bearing a friction axis intercept can be obtained depending upon a source parameter, q. With cos α ≈ b/2, a rapid rise in the co-efficient of friction can also be simulated by properly varying the source parameter. Also, lubricant end flow increases monotonically as the Sommerfeld variable approaches zero.

The Distribution of Light from Optical Systems

1949 ◽  
Vol 2 (3) ◽  
pp. 335
Author(s):  
WH Steel
Keyword(s):  
Point Source ◽  
Optical System ◽  
Optical Axis ◽  
Spherical Aberration ◽  
Light Distribution ◽  
Optical Systems ◽  
Geometrical Method ◽  
Plane Normal ◽  
Finite Source

A geometrical method is developed for calculating the distribution of intensity with angle of the light leaving an optical system, when the angle at which a ray from a point on the optical axis leaves the system is known as a function of the aperture. The case of a point source on the axis of the system is treated exactly, and an approximation is given for that of a small finite source ; the method is applicable to systems with spherical aberration. The distribution of illumination across any plane normal to the axis is treated by analogous methods. The results are compared with measurements of the light distribution from an optical system possessing considerable spherical aberration.

CBED Shadow Images and Cs:Aberration Measurement

1982 ◽  
Vol 40 ◽  
pp. 696-697
Author(s):  
R. W. Carpenter ◽  
I.Y.T. Chan ◽  
J. M. Cowley
Keyword(s):  
Focal Point ◽  
Spherical Aberration ◽  
Optic Axis ◽  
Wide Angle ◽  
Caustic Surface ◽  
Convergent Beam

Wide-angle convergent beam shadow images(CBSI) exhibit several characteristic distortions resulting from spherical aberration. The most prominent is a circle of infinite magnification resulting from rays having equal values of a forming a cross-over on the optic axis at some distance before reaching the paraxial focal point. This distortion is called the tangential circle of infinite magnification; it can be used to align and stigmate a STEM and to determine Cs for the probe forming lens. A second distortion, the radial circle of infinite magnification, results from a cross-over on the lens caustic surface of rays with differing values of ∝a, also before the paraxial focal point of the lens.

Analysis of 3-d molecular distribution with the digital imaging microscope

1988 ◽  
Vol 46 ◽  
pp. 40-41
Author(s):  
W.A. Carrington ◽  
F.S. Fay ◽  
K.E. Fogarty ◽  
L. Lifshitz
Keyword(s):  
Image Restoration ◽  
Digital Imaging ◽  
Fluorescent Dyes ◽  
Optical Axis ◽  
Computer Hardware ◽  
Computer Algorithms ◽  
Low Contrast ◽  
Specific Proteins ◽  
Effective Use ◽  
Single Living Cells

Advances in digital imaging microscopy and in the synthesis of fluorescent dyes allow the determination of 3D distribution of specific proteins, ions, GNA or DNA in single living cells. Effective use of this technology requires a combination of optical and computer hardware and software for image restoration, feature extraction and computer graphics.The digital imaging microscope consists of a conventional epifluorescence microscope with computer controlled focus, excitation and emission wavelength and duration of excitation. Images are recorded with a cooled (-80°C) CCD. 3D images are obtained as a series of optical sections at .25 - .5 μm intervals.A conventional microscope has substantial blurring along its optical axis. Out of focus contributions to a single optical section cause low contrast and flare; details are poorly resolved along the optical axis. We have developed new computer algorithms for reversing these distortions. These image restoration techniques and scanning confocal microscopes yield significantly better images; the results from the two are comparable.

Field Distribution of Strongly Excited Magnetic Lenses

1975 ◽  
Vol 33 ◽  
pp. 140-141
Author(s):  
M. Strojnik
Keyword(s):  
Flux Density ◽  
Field Distribution ◽  
Optical Axis ◽  
Operating Point ◽  
Pole Piece ◽  
Partial Saturation ◽  
Axial Flux ◽  
The Stability

Magnetic lenses operating in partial saturation offer two advantages in HVEM: they exhibit small cs and cc and their power depends little on the excitation IN. Curve H, Fig. 1, shows that the maximal axial flux density Bz max of one of the lenses investigated changes between points (3) and (4) by 5% as the excitation varies by 40%. Consequently, the designer can relax the requirements concerning the stability of the lens current supplies. Saturated lenses, however, can only be used if (i) unwanted fields along the optical axis can be controlled, (ii) 'wobbling' of the optical axis due to inhomogeneous saturation around the pole piece faces is prevented, (iii) ample ampere-turns can be squeezed into the space available, and (iv) the lens operating point covers a sufficient range of accelerating voltages.

XRMF applications of a monolithic, polycapillary, focusing x-ray optic

1996 ◽  
Vol 54 ◽  
pp. 240-241
Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla
Keyword(s):  
Trace Elements ◽  
Point Source ◽  
Focal Spot ◽  
Fluorescence Analysis ◽  
X Rays ◽  
Focal Distance ◽  
Spot Diameter ◽  
X Ray ◽  
Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

Sign in / Sign up

Export Citation Format

Share Document