摘要:

SUMMARYContrast effects from electron channelling in crystalline solids can be observed in the scanning electron microscope by the correct choice of operating conditions. The crystallographic symmetry and orientation of specimen areas as small as 1 μm in diameter can be determined, and detailed quantitative information obtained about the density, nature and position of defects contained within the crystal structure. The backscattered, absorbed current and transmitted electron signals may all be used. With anticipated improvements in instrumentation the technique will be capable of providing all the information currently supplied by the more complex procedures of transmission electron microscopy

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04533.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYScanning electron microscope images are subject to an appreciable amount of non‐linear distortion which must be allowed for when quantitative analyses are made. A method is described for measuring the distortion by the use of moiré patterns. These greatly magnify any non‐linearities and it is possible to measure distortions as small as 0ṁ1%. In addition, the use of moiré patterns permits a separation of the distortion produced in the cathode‐ray display tube from that occurring in the microsco

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04534.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYSingle atom image intensities are calculated for bright‐field and various dark‐field modes, including the ideal beam stop, a wire beam stop, tilted illumination and a displaced aperture. Comparisons of scattering amplitudes and elastic scattering cross‐sections are made with different object potentials and scattering formulations. The image contrast for one mercury atom (Z= 80) on a column of carbon atoms (Z= 6) as the substrate is also discussed for both the bright‐field and the various dark‐field situations. A list of abbreviations to be used in the text is sh

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04535.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYLattice (Fourier) images of crystallites in human bone and teeth, and calcified atherosclerotic plaque were studied using high resolution transmission electron microscope techniques. The lattice images observed in the normal and diseased calcified tissue were compared with the images of synthetic hydroxyapatite crystallites.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04536.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYThe use of silver as a ‘stain’ for nerve fibres in scanning electron microscopy (SEM) preparations has been investigated. Samples of cardiac tissues were treated according to the Bielschovsky silver impregnation method. Following embedding in paraffin, successive sections were selected for light microscopy and for SEM studies, respectively. The silver impregnated fibres, when examined in SEM preparations, appeared nearly white against a greyish background of cardiac tissue. They were therefore easy to localize even at a low magnification. These nerve fibres were identified in the same tissue, but different blocks by means of transmission electron microscopy (TEM) studies and by fluoroescence microsc

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04537.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYA modification to the vacuum system of a JSM2 scanning electron microscope has enabled hydrated specimens to be placed inside the specimen chamber of the instrument and to be surrounded by water vapour at a pressure up to approximately 1.3 kPa (10 Torr). The surface topography was observed by detecting the backscattered electrons using a wide angle backscattered electron detector placed close to the specimen. The microscope was operated in the normal scanning mode which allowed the examination of the surface topography of the specimens, whilst still retaining the depth of focus which is a feature of the SEM.This modification has enabled a resolution of approximately 0.2 μm to be obtained from biological specimens partially immersed in water at temperatures just above 0°

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04538.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYFactors governing photographic image quality in the scanning electron microscope are discussed with particular reference to the commonly used EXA camera on the Cambridge Stereoscan IIa. It is shown that the small image on the medium speed film suffers considerable loss of information due to the turbid nature of the photographic emulsion. Inexpensive modifications to the oscilloscope camera supplied with the Stereoscan are described which enable the superior quality of a larger format to be utilized. Appropriate settings of the brightness and contrast controls of the image tube with respect to the photographic system is discussed and the results illustrated in a series of micrographs.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04539.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYNematodes from the orders Tylenchida and Rhabditida were fixed and processed in several different ways for examination with the scanning electron microscope (SEM). Four processes produced good preparations of fixed nematodes. Drying from acetone was the simplest of these techniques and most useful for regions of the tylenchid nematodes supported by skeletal tissue. Critical point drying, a more complicated procedure, gave good preparations but they required special care in processing. Nematodes infiltrated with glycerol and a conducting agent were the most life‐like but were difficult to examine. Specimens infiltrated with an epoxy resin looked natural and this was the most promising process trie

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04540.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYComparative morphological examination and elemental analysis were carried out in structural compartments of sections of skeletal muscles. These had been prepared either by conventional plastic embedding technique or by various methods of cryo‐ultramicrotomy. The analyses were performed in a Philips EM 301 with an Edax energy‐dispersive X‐ray spectrometer.Spectra obtained from sections of plastic‐embedded muscle depended on the reagents used for fixation and staining and were absent if these were omitted. Brief fixation with glutaraldehyde resulted in gross ionic changes, and sectioning of frozen material with trough liquid led to extraction of elements. Sections cut from unfixed and frozen muscle without trough liquid showed numerous peaks. (Mg, P, S, Cl, K, Ca). In the superficial parts of the fibres of freeze‐dried sections reproducible spectral differences were found between different structures. Thus, rapid freezing of unfixed tissue, dry cutting in the frozen state, and freeze‐drying should be the procedure of choice if data on diffusible ions

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04541.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SUMMARYGlass knives for ultramicrotomy were considerably improved by coating the cutting edge with a film of evaporated tungsten metal. Knives treated by this method gave up to ten times as many acceptable sections as uncoated glass knives. They could also cut thinner sections and harder tissues than ordinary glass knives, and eliminated some of the cutting artefacts produced by them. No explanation for this improvement was found although several possibilities were examined.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1975.tb04542.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY