Исследование динамических процессов, реализующихся при генерации плазмоидных образований в сверхзвуковом потоке

An analysis of plasma dynamic processes and shock waves interactions in supersonic jet at plasma spherical formation initiation was made using the high-speed digital image recording. The dynamics of the spherical plasmoid which creates discontinuities, affecting the bow shock wave in front of the model was investigated with a high temporal resolution. It was shown that during the time of plasmoid electric current (about 100-130 microseconds) the structure of supersonic flow around the model changes: the shock layer is transformed, bow shock wave detached distance on the symmetry axis is significantly increased due to a change of oncoming flow parameters and structure.

Effective Extinction Distances in Zone Axis Silicon

Many scientific questions encountered in electron microscopy require quantitative deductions from the observations. Comparisons of experimental observations with simulations are however, still relatively rare since measurements of intensity are normally difficult. In this paper we discuss the use of experimental observations of the effective extinction distances for zone axis silicon using a convergent beam STEM mode for comparison with a number of simulations. On the experimental side, the measurements were made with a STEM that provides accurate intensity measurements directly with a digital image recording system. Two theoretical schemes widely used in electron microscopy simulations, multislice simulation and Bloch-wave calculation, were employed for the simulations. In each case, both a TEM case and a STEM case were calculated for comparison.The multislice simulations were carried out using codes available from Kirkland. For the TEM case with plane waves at normal incidence on the sample surface, the unscattered (0,0) exit beam gives the Bright Field (BF) intensity.

The CM120-Biofiiter: Digital Imaging Of Frozen Hydratedspecimens and Elemental Mapping

A new system for energy-filtered electron microscopy (EFTEM) has been developed, adapted for the study of life science specimens. Special attention has been given to integration, ease of use and the typical problems encountered while investigating unstained and cryo-specimens. Low-dose, cryocapabilities and a high-contrast objective lens have been combined with an imaging energy filter, digital image recording with phosphor scintillator and advanced image-processing capabilities. The CM120-BioFilter is an integration of the CM120-BioTWIN or the CM120TWIN with the Gatan postcolumn imaging filter GIF100. The BioTWIN objective lens (Cs=6.2 mm, f=5.9 mm) is optimized for high-contrast imaging. The TWIN lens(Cs=2mm,f=2.8mm) is optimized for high resolution in structural biology. The GIF 100 is a computer-controlled, second-order corrected energy filter with a cooled multiscan CCD for digital image recording. Improvement of the contrast can be achieved if inelastically scattered electrons are removed.

The CM120-Biofilter: Digital Imaging of Unstained Specimen, a Comparison of Zero-Loss and Unfiltered Images

A new system for energy-filtered electron microscopy (EFTEM) has been developed, adapted for the study of life science specimens. Attention has been given to integration, ease of use and the typical problems encountered while investigating unstained and cryo-specimens. Low-dose, cryo-capabilities and a high contrast objective lens have been combined with an imaging energy filter, digital image recording with phosphorus scintillator and advanced image processing capabilities. The CM120-BioFilter is an integration of the CM 120-BioTWIN with the Gatan post-column imaging filter GIF100. The BioTWIN objective lens (Cs=6.2 mm, f=5.9 mm) is optimized for high-contrast imaging. The GIF100 is a computer-controlled, second- order corrected energy filter with a cooled multiscan CCD for digital image recording. Improvement of the contrast can be achieved if inelastically scattered electrons are removed. A comparison of zero-loss filtered and unfiltered images from unstained specimens is presented.The contrast of thick, unstained specimens is limited by the high amount of inelastic scattering. Images from thick sections of unstained spleen tissue shown in Fig. 1 are compared by means of mean and standard deviation of multiscan CCD data.

A Simple and Inexpensive Route to Remote Electron Microscopy

Due to the availability of fast computer networks such as Ethernet, FDDI and ATM, the idea of Telemicroscopy, including running electron microscopes from remote locations has gained momentum. Fan, Ellisman, Zaluzec and Parvin, have discussed aspects of systems which support such capabilities. In each of these reports the authors describe new stand-alone software packages that are required to run their systems. In order to make remote microscopy more universally available, we have chosen to expand de facto standard commercial software to provide for computerized microscope control and remote control.All of the major instruments in our user facility have been converted to digital operation and the darkroom has been abandoned completely. It is a logical extension of digital imaging to provide for computer control of the instrument operation, since the instrument parameters can be adjusted using feedback from analysis of the digital image. Digital image recording and display typically uses commercial software such as DigitalMicrograph© (which controls e.g. the CCD camera on the HF-2000). This program provides the four capabilities necessary to implement instrument control. It allows camera control,provides image processing tools, incorporates a scripting language and also allows C-code to be implemented.

Digital imagery for making plates

Although the resolution and depth of focus provided by scanning electron microscopy (SEM) revolutionized the examination of several groups of microfossils, conventional photographic techniques are normally outlined in instructions for preparation of micrographs for publication (Whittaker & Hodgkinson, 1991). While the quality of results attainable by following these methods is very high, digital image recording and processing techniques are now well developed and readily available. This note outlines some advantages of digital techniques in the preparation of SEM images for publication.DIGITAL RECORDINGSecondary electron and other detectors attached to the SEM produce analogue (waveform) signals. In early instruments only these analogue signals were processed and displayed. Modern designs quantize signals from the detector as pixels (picture elements) which represent grey levels along scan lines. Pixel information is processed by the SEM on-board computer and saved as an image file. Importantly, the basic hardware to convert the analogue signal to digital form is simple and can be readily retro-fitted to early instruments. Our Philips PSEM 500 was adapted to record 128 grey levels at 800 pixels/line over 600 lines/frame, a minimum specification for professional work. Many micropalaeontologists will find that their SEM laboratories can supply digital files at higher resolutions. However, an essential point is to work with images recorded digitally directly from the SEM video channel, so avoiding potential degradation due to scanning of images recorded on film from the SEM monitors.DIGITAL PROCESSINGI use Photostyler (a PC image editor by Aldus Corp.) for plate composition. It resembles. . .