A critical examination of submicron optical lithography using simulated projection images

1983 ◽  
Vol 1 (4) ◽  
pp. 1190 ◽  
Author(s):  
Alan E. Rosenbluth
Keyword(s):  
Optical Lithography ◽  
Critical Examination ◽  
Projection Images

Imaging of platinum-shadowed macromolecular complexes in dark field

1984 ◽  
Vol 42 ◽  
pp. 146-147
Author(s):  
D.W. Andrews ◽  
F.P. Ottensmeyer
Keyword(s):  
Thin Film ◽  
Three Dimensional ◽  
Average Diameter ◽  
Dark Field ◽  
Bright Field ◽  
Field Mode ◽  
Macromolecular Complexes ◽  
Average Mass ◽  
Topological Features ◽  
Projection Images

Shadowing with heavy metals has been used for many years to enhance the topological features of biological macromolecular complexes. The three dimensional features present in directionaly shadowed specimens often simplifies interpretation of projection images provided by other techniques. One difficulty with the method is the relatively large amount of metal used to achieve sufficient contrast in bright field images. Thick shadow films are undesirable because they decrease resolution due to an increased tendency for microcrystalline aggregates to form, because decoration artefacts become more severe and increased cap thickness makes estimation of dimensions more uncertain.The large increase in contrast provided by the dark field mode of imaging allows the use of shadow replicas with a much lower average mass thickness. To form the images in Fig. 1, latex spheres of 0.087 μ average diameter were unidirectionally shadowed with platinum carbon (Pt-C) and a thin film of carbon was indirectly evaporated on the specimen as a support.

Semi-automated methods for 3-D reconstruction of macromolecular complexes

1995 ◽  
Vol 53 ◽  
pp. 42-43
Author(s):  
B. Carragher ◽  
M. Whittaker
Keyword(s):  
Three Dimensional ◽  
Time Saving ◽  
Macromolecular Complexes ◽  
Symmetry Properties ◽  
Dimensional Reconstruction ◽  
Experienced Operator ◽  
Projection Images ◽  
The Individual ◽  
Natural Symmetry

Techniques for three-dimensional reconstruction of macromolecular complexes from electron micrographs have been successfully used for many years. These include methods which take advantage of the natural symmetry properties of the structure (for example helical or icosahedral) as well as those that use single axis or other tilting geometries to reconstruct from a set of projection images. These techniques have traditionally relied on a very experienced operator to manually perform the often numerous and time consuming steps required to obtain the final reconstruction. While the guidance and oversight of an experienced and critical operator will always be an essential component of these techniques, recent advances in computer technology, microprocessor controlled microscopes and the availability of high quality CCD cameras have provided the means to automate many of the individual steps.During the acquisition of data automation provides benefits not only in terms of convenience and time saving but also in circumstances where manual procedures limit the quality of the final reconstruction.

Effects of Nonspeech Contexts on Speech Categorization: A Critical Examination

2007 ◽  
Author(s):  
Navin Viswanathan ◽  
James S. Magnuson ◽  
Carol A. Fowler
Keyword(s):  
Critical Examination ◽  
Speech Categorization

IPOMOEA LITTORALIS AND IPOMOEA CAPITELLATA VAR. MULTILOBATA : NEW RECORDS FOR UPPER GANGETIC PLAINS OF INDIA

2018 ◽  
Vol 24 (1) ◽  
Author(s):  
JASWINDER KAUR ◽  
SATYA NARAIN
Keyword(s):  
New Records ◽  
Critical Examination ◽  
Type Specimens ◽  
Gangetic Plains

The floristic exploration and critical examination of specimens collected of family Convolvulaceae from Upper Gangetic Plains of India, resulted in addition of 2 new records for the flora viz. Ipomoea littoralis and Ipomoea capitellata var. multilobata. Detailed description, phenology, ecology, distribution, locality, field number, type specimens examined, illustrations and other relevant notes are provided.

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