Search results for "Aberration"

Inherited semisterility for control of harmful insects. V. Translocations in Culex tritaenio-rhynchus.

1972

Mit unterschiedlichen Dosen von Rontgenstrahlen wurden bei der StechmuckeCulex tritaeniorhynchus chromosomale Aberrationen (vorwiegend reziproke Translokationen) produziert, die von der zweiten Tochtergeneration an einen konstanten Grad von Semisterilitat zeigen. Die Mehrzahl der isolierten Linien zeigte im Durchschnitt eine Letalitat von etwa 50%. Die Variationsbreite innerhalb einer Linie betrug ±10–15%. Durch cytologische Untersuchungen von Prophasechromosomen wurden die geschlechtsbestimmenden Faktoren M und m auf einem der beiden langen Chromosomen lokalisiert.

Multi or Single-Kinase Inhibitors to Counteract Drug Resistance in Cancer: What is New?

2023

The concept of protein kinase inhibition starts from the groundbreaking research on the role of these proteins in the regulation of fundamental processes, including proliferation, cell cycle, apoptosis, metabolism, and inflammation. Kinase genetic mutations, as well as overexpression and dysregulation, can contribute to the development of several diseases, including neoplasms, leading to relapses and resistance to standard drug chemotherapy [1-3].

Optical demultiplexing of millimeter-wave subcarriers for wireless channel distribution employing dual wavelength FBGs

2007

An optical mm-wave demultiplexer is presented. Double sideband modulation with suppressed optical carrier and filtering properties of dual overwritten fiber Bragg gratings are the fundamentals for optical demultiplexing of mm-wave radio-on-fiber signals: using a single optical carrier, Millimeter-wave signals of 20 and 40 GHz frequencies carrying independent data are created, transmitted over fiber, demultiplexed and wireless distributed to be detected and data recovered in a mobile unit. Double sideband modulation with suppressed optical carrier yields no power penalty due to chromatic dispersion, while the filtering properties of the dual overwritten fiber Bragg gratings allow less than −…

Achromatic Fresnel diffraction patterns

1993

Abstract A novel method for obtaining a single, but arbitrary, achromatic Fresnel diffraction pattern of any pupil with broadband parallel illumination is presented. The optical device simply consists of an achromatic objective and an on-axis zone plate. A criterion for selecting the system parameters in order to minimize the residual chromatic aberrations is given. The recording of the selected diffraction field is obtained with low chromatic aberrations even for white-light illumination. An experimental verification is shown to illustrate this approach.

White-light Fourier transformer with low chromatic aberration.

1992

A simple Fourier transformation system working with broadband parallel illumination is presented. The proposed setup, consisting of two on-axis zone plates and an achromatic objective, allows us to obtain the achromatic Fourier transform representation of the input at a finite distance with a low chromatic aberration. The discussion of the system, using the Fresnel diffraction theory, leads to an analytical expression to evaluate the transversal and longitudinal chromatic aberrations. It is shown that the resulting chromatic aberrations for typical values of the involved parameters are less than 1% over the entire visible spectrum.

Quasi-wavelength-independent broadband optical Fourier transformer

1999

The chromatic behaviour associated with diffractive optical elements is exploited herein to design a hybrid (diffractive-refractive) lens triplet showing very great wavelength-compensation capabilities for the Fraunhofer diffraction pattern of any diffracting screen under broadband point-source illumination. Within the paraxial Fresnel diffraction theory, we show that perfect compensation for the axial position of the Fourier transform of the input can be accomplished if we neglect the secondary spectrum of the refractive objective. Simultaneously, an achromatic correction for the scale of the Fraunhofer pattern is achieved. In this way, even for white light, only a low residual transversal…

Analysis of the irradiance along different paths in the image space using the Wigner distribution function

1997

Abstract The intensity distribution along different paths in the image space of an optical system is described in a two-dimensional phase-space domain in terms of the Wigner distribution function. This approach is useful for an efficient analysis of the performance of optical imaging systems suffering from spherical aberration. The good performance of the method is shown in some numerical simulations.

Bifractal focusing and imaging properties of Thue-Morse Zone Plates.

2015

We present a new family of Zone Plates (ZPs) designed using the Thue-Morse sequence. The focusing and imaging properties of these aperiodic diffractive lenses coined Thue-Morse Zone Plates (TMZPs) are examined. It is demonstrated that TMZPs produce a pair of self-similar and equally intense foci along the optical axis. As a consequence of this property, under broadband illumination, a TMZP produces two foci with an extended depth of focus and a strong reduction of the chromatic aberration compared with conventional periodic ZPs. This distinctive optical characteristic is experimentally confirmed.

Chromatic and Spherical Aberration Correction Using Time-Dependent Acceleration and Lens Fields

2003

Modulation transfer function of a toric intraocular lens: evaluation of the changes produced by rotation and tilt.

2011

PURPOSE: To evaluate the changes in optical quality when toric intraocular lenses (IOL) are rotated or tilted and to demonstrate that IOL rotation produces an increasing effect of aberrations. METHODS: Modulation transfer function (MTF) and average modulation were used to analyze the image quality of a toric IOL. The axis of the toric IOL was rotated 5°, 10°, 15°, 20°, 25°, and 30° in successive MTF measurements. The tilt values were 0° to 5°, in increments of 1°, plus a tilt of 15°. Pupil diameters of 3 and 5 mm were used. RESULTS: The MTF decay due to aberrations was more sensitive to rotation than tilt. The main decrement in the average modulation, of approximately 50% in both pupils, o…