摘要:

SUMMARYThe Hughes liquid crystal light valve has been coupled to a transmission electron microscope using a fibre optics plate and transmission phosphor. This system makes it possible to reconstruct in real time, electron images in coherent or incoherent light of arbitrary intensity outside the vacuum. The experimental results reported are used to estimate the design parameters of an on‐line coherent optical diffractometer for high resolution wor

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04129.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYThe scattering matrix formalism used for the cases of translation and inversion boundaries is generalized to any type of interface in homogeneous crystals. The present method needs no arbitrary decompositions of the diffracting sets in the lower crystal. It leads to conditions of stacking‐fault‐like contrast, different from those proposed by Sutton&Pond, in agreement with experime

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04130.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYOptical diffraction techniques have a wide range of applications which extend from the further interpretation of electron micrograph images to aerial photographs. Useful metallographic applications are based on optical or electron micrographs.A brief account is given of a typical system for obtaining optical transforms or diffraction patterns and reconstituted images. Structures which appear frequently in eutectics or eutecoids show laminations arising from the alternating formation of different constituents with planar interfaces. The diffraction patterns are relatively simple but may be affected by variations in spacing and orientation. Account should also be taken of geometrical and other factors due to the tilt of the lamellae with respect to the surface. Besides recording the spacings it is also useful to take account of the directions of traces in the surface in view of the possible presence of structural anisotropy.The eutectic which is the sole constituent in alloys containing aluminium with 33% copper provides a useful illustration of the principles. Some typical results are briefly presented.A second application refers to ‘pearlite’, the eutectoid which forms in iron‐carbon alloys and many carbon and low alloy steels. The alternating lamellae are α‐iron and the carbide Fe3C. Two examples are given. The first refers to the use of spacing measurements in order to examine the dependence on temperature of transformation. The second shows how statistical spacing variations in a micrograph may reveal whether there is one or more basic spacing. The variation of the trace directions reveals structural anisotropy, and the relation of the spacing to this anisotropy is also

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04131.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYA method for size distribution analysis of liposome suspensions is described. Spray‐freezing was used in order to avoid cryoprotectants and fixatives. Light scattering showed that, depending on their composition, liposomes can be modified by the spraying procedure. Dipalmitoylphosphatidylcholine liposome suspensions display large modifications of light scattering upon spraying. The commonly used unilamellar phosphatidylserine/phosphatidylcholine (1:4) liposomes, with or without cholesterol, are, however, only slightly affected by the spraying procedure.For liposome suspensions stable upon spraying, size distribution analysis can be performed on freeze‐fracture replicas by standard procedures and average size, area and volume of particles are obtained. The number of particles per unit volume cannot be determined by stereological procedures, since the fracture face does not correspond to a plane section through the sample. By combining stereological data with phospholipid mass and specific molecular area of phospholipids, abundance of particles, fractional volume and total membrane area can nevertheless be evaluated.Data on small unilamellar liposomes prepared by sonication are presented as an illustration of the method. In suspensions obtained by this procedure, vesicles may be considered at thermodynamic equilibrium in the aqueous phase. The experimental size distribution compared favourably with that obtained from self‐assembly theory for liposomes, considering natural lecithin heterogeneity. For comparison purposes, data on large unilamellar liposomes, obtained by reverse‐phase evaporation, are also pr

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04132.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYA technique is described for utilizing the 35 mm microfilm plotting facilities, available at some large computer centres, as a means of portraying calculated electron microscope images. Examples related to images of single layers of carbon are given.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04133.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYTransmission electron microscopy is used in an investigation of crocidolite asbestos associated with two biological systems. Control material is extremely defective and contains in particular an abundance of Wadsley defects, (100) planar faults, and pores. Fibres sectioned in lung tissue and fibres taken fromin vitroexposure to blood serum show evidence of erosion by two mechanisms—preferential attack at (100) planar defects and general surface dissolutio

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04134.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYAcoustic micrographs of human metaphase chromosomes have been recorded with wavelengths as short as 470 nm using liquid argon near 85 K as the acoustic wave coupling medium. Chromosomes prepared by trypsin‐Giemsa staining exhibit acoustic banding patterns similar to the G‐bands seen in optical images. Unstained chromosomes exhibit acoustic markings that do not correspond to traditional banding patterns. The observed acoustic contrast may arise from spatial variations in chromosomal mechanical properties, or from thickness variations in the fixed chromoso

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04135.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYA technique is described for obtaining 1 μm sections of tissue embedded in modified paraffin wax using long‐edged glass knives. Serial sections can be cut and stained by the immunoperoxidase method to demonstrate multiple antigens in a single cell or to confirm that the immunoglobulin within a cell is monotypic. The improved cytological detail seen in thin paraffin sections permits the more precise localization of intracellular staini

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04136.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYA method of measuring transmitted beam current stability during and between X‐ray microanalyses in a STEM is described. This facility also allows analytical artefacts due to charging, drift, contamination and mass loss to be detected during an analysi

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04137.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARYA pulse‐stretch analyser attached to an Energy Dispersive Spectrophotometer for the simultaneous mapping of two or more elements is described. The circuit for the instrument is given and examples of variable spot‐size maps which may be generated, are shown by the distribution of Si, Ti and Cr in polished grains of ilmenite, garnet, spinel and clinopyrox

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1980.tb04138.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY