نتایج جستجو برای: minimum aberration
تعداد نتایج: 172536 فیلتر نتایج به سال:
Three radially symmetric and two first order rotational test targets were systematically tested for sensitivity and orthogonality by observing the change in the onaxis image intensity from the unaberrated cases in the presence of 0.05 waves peak of the corresponding 5 aberrations. The results are shown in Figure 4. Here each column corresponds to one of the test targets and each row corresponds...
Design of a new aberration corrected Photoemission electron microscope PEEM3 at the Advanced Light Source is outlined. PEEM3 will be installed on an elliptically polarized undulator beamline and will be used for the study of complex materials at high spatial and spectral resolution. The critical components of PEEM3 are the electron mirror aberration corrector and aberration-free magnetic beam s...
METHODS: Assuming that cyclotorsion error can be estimated and compensated for with a certain level of uncertainty, we formulate a function to modify the wavefront error in order to minimize the residual aberration magnitudes due to cyclotorsion measurement uncertainty. A modal optimum nomogram factor is computed for minimization of the residual aberration for each Zernike mode. We also calcula...
Exposure to ionizing radiations, whether medical, occupational or accidental, leads to deleterious biological consequences like mortality or carcinogenesis. It is considered that no dose of ionizing radiation exposure is safe. However, once the accurate absorbed dose is estimated, one can be given appropriate medical care and the severe consequences can be minimized. Though several accurate phy...
The methodology of cytogenetic triage can be improved by optimizing a schedule of microscopy for different exposure scenarios. Chromosome aberrations were quantified by microscopy in human blood lymphocytes irradiated in vitro to ~2, 4, and 12 Gy acute 60Co γ-rays mixed with the unirradiated blood simulating 10%, 50%, 90%, and 100% exposure and in along with a sample from a homogeneous exposure...
Expressions for describing Gaussian beams focused by a lens with spherical aberration have been derived. Numerical results show that, when the coefficient of the spherical aberration is negative, one can obtain flattened laser irradiance at two positions along the focused field. The larger the coefficient of negative spherical aberration, the larger the flatness is. The effect of the Fresnel nu...
The solar grating spectrometer is an essential tool to study the thermodynamics properties of the solar atmosphere with different height distributions, but its imaging performance will be degraded by the wavefront aberration generalized by the atmospheric turbulence. On the other hand, the narrow slit of the grating spectrometer will filter the wavefront aberration to some extent. The influence...
The achievable resolution of a modern transmission electron microscope (TEM) is mainly limited by the inherent aberrations of the objective lens. Hence, one major goal over the past decade has been the development of aberration correctors to compensate the spherical aberration. Such a correction system is now available and it is possible to improve the resolution with this corrector. When high ...
We enjoyed reading the article by Esteve-Taboada et al.,1 but were disappointed by their interpretation of their data. Their optical model has important limitations that make it inappropriate to make broad clinical generalizations from their findings. First, the “aberration-free” eye model is highly artificial. In particular, the absence of any spherical aberration is relevant to only a small p...
PURPOSE To investigate corneal spherical aberration and corneal asphericity after small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). METHODS This study enrolled 70 patients having SMILE and 64 subjects receiving FS-LASIK. The preoperative spherical equivalent (SE) was -5.83 ± 1.23 diopters (D) and -6.20 ± 1.52 D, respectively. T...
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