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The effect of the contrast transfer function can be seen in the alternating light and dark rings (Thon rings), which show the relation between contrast and spatial frequency. The contrast transfer function (CTF) mathematically describes how aberrations in a transmission electron microscope (TEM) modify the image of a sample.
For instance, high intensity might or might not indicate the presence of an atom column in that precise location (see simulation). The relationship between the exit wave and the image wave is a highly nonlinear one and is a function of the aberrations of the microscope. It is described by the contrast transfer function.
The point spread function (PSF) describes the response of a focused optical imaging system to a point source or point object. A more general term for the PSF is the system's impulse response; the PSF is the impulse response or impulse response function (IRF) of a focused optical imaging system. The PSF in many contexts can be thought of as the ...
Wheeler's cosmic interferometer uses a distant quasar with two paths to equipment on Earth, one direct and one by gravitational lensing. After [2]. In an attempt to avoid destroying normal ideas of cause and effect, some theoreticians [who?] suggested that information about whether there was or was not a second beam-splitter installed could somehow be transmitted from the end point of the ...
As in any emission electron microscope, the objective or cathode lens determines the resolution. The latter is dependent on the electron-optical qualities, such as spherical aberrations, and the energy spread of the photoemitted electrons. The electrons are emitted into the vacuum with an angular distribution close to a cosine square function.
A live-cell microscope. Live-cell microscopes are generally inverted. To keep cells alive during observation, the microscopes are commonly enclosed in a micro cell incubator (the transparent box). Live-cell imaging is the study of living cells using time-lapse microscopy.
Within molecular and cell biology, temporal feedback, also referred to as interlinked or interlocked feedback, is a biological regulatory motif in which fast and slow positive feedback loops are interlinked to create "all or none" switches. This interlinking produces separate, adjustable activation and de-activation times.
A scanning transmission electron microscope (STEM) is a type of transmission electron microscope (TEM). Pronunciation is [stɛm] or [ɛsti:i:ɛm]. As with a conventional transmission electron microscope (CTEM), images are formed by electrons passing through a sufficiently thin specimen. However, unlike CTEM, in STEM the electron beam is focused ...