Results 251 to 260 of about 91,983 (282)
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Rigorously aplanatic Descartes ovoids
Journal of the Optical Society of America A, 2021It is known that, besides being stigmatic, spherical refracting surfaces are aplanatic at their Young points since they satisfy the Abbe sine condition rigorously. The Abbe sine condition is commonly applied to different optical systems using numerical methods or optimization processes, obtaining a design of approximately aplanatic systems.
Alberto Silva-Lora, Rafael Torres
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American Journal of Roentgenology, 1969
An afterloading modification of the Fletcher vaginal ovoids for gynecologic radium therapy is described and illustrated. The afterloading ovoids have proven to be of great value in over 500 patient applications during the past 4 years. The many advantages of use of the afterloading system are stressed.
A E, Green +2 more
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An afterloading modification of the Fletcher vaginal ovoids for gynecologic radium therapy is described and illustrated. The afterloading ovoids have proven to be of great value in over 500 patient applications during the past 4 years. The many advantages of use of the afterloading system are stressed.
A E, Green +2 more
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Achromatic stigmatism: achromatic Cartesian ovoid
Journal of the Optical Society of America A, 2022Monochromatic and chromatic aberrations are imaging defects mainly studied from a geometrical optics point of view. These defects are treated through optimization and minimization methods to achieve acceptable performance in optical imaging systems, where the correct choice of glass materials is one of the main challenges.
Alberto Silva-Lora, Rafael Torres
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Geometriae Dedicata, 2000
The authors prove various results on ovoids of \(Q(6,q)\) and \(Q(4,q)\), the parabolic quadrics in, respectively, 6- and 4-dimensional projective space over the finite field of \(q\) elements. These results go from very well known ``folklore'' to constructing a new ovoid in \(Q(4,3^5)\).
Penttila, Tim, Williams, Blair
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The authors prove various results on ovoids of \(Q(6,q)\) and \(Q(4,q)\), the parabolic quadrics in, respectively, 6- and 4-dimensional projective space over the finite field of \(q\) elements. These results go from very well known ``folklore'' to constructing a new ovoid in \(Q(4,3^5)\).
Penttila, Tim, Williams, Blair
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2014
Rouillieria aff. ovoides (Sowerby, 1815) Fig. 8.9–8.16 1971b aff. Rouillieria ovoides (J. Sowerby) —Ager, p. 394, pl. 14, pl. 15, fig. A. Material and occurrence. Seep 8 (PMO 224.924, PMO 224.926, PMO 224.931–932), seep 13 (PMO 224.906, PMO 227.426). Description. Quadrate outline, equally biconvex profile, rectimarginate anterior commissure. Discussion.
Sandy, Michael R. +4 more
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Rouillieria aff. ovoides (Sowerby, 1815) Fig. 8.9–8.16 1971b aff. Rouillieria ovoides (J. Sowerby) —Ager, p. 394, pl. 14, pl. 15, fig. A. Material and occurrence. Seep 8 (PMO 224.924, PMO 224.926, PMO 224.931–932), seep 13 (PMO 224.906, PMO 227.426). Description. Quadrate outline, equally biconvex profile, rectimarginate anterior commissure. Discussion.
Sandy, Michael R. +4 more
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Journal of the London Mathematical Society, 1997
The only known classes of ovoids in 3-dimensional projective spaces over fields of even order are the elliptic quadrics and the Tits ovoids. The authors present a common characterization of these two classes as follows. An ovoid \(\mathcal O\) of PG\((3,q)\), where \(q > 2\) is even, is an elliptic quadric or a Tits ovoid if and only if \(\mathcal O ...
Penttila, Tim, Praeger, Cheryl E.
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The only known classes of ovoids in 3-dimensional projective spaces over fields of even order are the elliptic quadrics and the Tits ovoids. The authors present a common characterization of these two classes as follows. An ovoid \(\mathcal O\) of PG\((3,q)\), where \(q > 2\) is even, is an elliptic quadric or a Tits ovoid if and only if \(\mathcal O ...
Penttila, Tim, Praeger, Cheryl E.
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Ovoidal blocking sets and maximal partial ovoids of Hermitian varieties
Designs, Codes and Cryptography, 2010zbMATH Open Web Interface contents unavailable due to conflicting licenses.
MARINO, Giuseppe, POLVERINO, Olga
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Superconical aplanatic ovoid singlet lenses
Journal of the Optical Society of America A, 2020In this work, we return to Descartes’s idea to develop a formalism to construct rigorously stigmatic singlet lenses comprising two Cartesian surfaces. Optical systems are built using a considerable number of spherical surfaces, presenting in most cases spherical aberration.
Alberto Silva-Lora, Rafael Torres
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Archives of Ophthalmology, 1983
In Reply. —We performed TEM on ovoid bodies in 1980 and presented our results at the 19th North Japan Ophthalmological Society, which was conducted in Asahikawa in June 1981. Our article was accepted for publication in theArchiveson Feb 24, 1982. The second edition of Yanoff and Fine's ocular pathology textbook was not published at that time.
A. Kurosawa, H. Kurosawa
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In Reply. —We performed TEM on ovoid bodies in 1980 and presented our results at the 19th North Japan Ophthalmological Society, which was conducted in Asahikawa in June 1981. Our article was accepted for publication in theArchiveson Feb 24, 1982. The second edition of Yanoff and Fine's ocular pathology textbook was not published at that time.
A. Kurosawa, H. Kurosawa
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Geometriae Dedicata, 1995
This paper focuses on ovoids of the Klein quadric \(Q^+ (5,q)\) admitting the symmetric group \(S_5\) as a group of automorphisms, and such that \(q\) and 30 are relatively prime, and \(q^2 - 1\) is not divisible by 5. Such an ovoid defines a translation plane of order \(q^2\) by the Klein correspondence.
Charnes, C., Dempwolff, U.
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This paper focuses on ovoids of the Klein quadric \(Q^+ (5,q)\) admitting the symmetric group \(S_5\) as a group of automorphisms, and such that \(q\) and 30 are relatively prime, and \(q^2 - 1\) is not divisible by 5. Such an ovoid defines a translation plane of order \(q^2\) by the Klein correspondence.
Charnes, C., Dempwolff, U.
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