Induction log modeling by a coupled‐mode multiple‐reflection series method

In induction logging, both vertical and radial conductivity variations exist in the logged medium; elementary separation of variables cannot be applied directly to the partial differential equation describing the electromagnetic field in such a medium. A modal expansion method of solution can be designed using modes defined with respect to the vertical coordinate. This method breaks the original two‐dimensional (2-D) problem into a set of independent one‐dimensional (1-D) problems. The receiver signal is decomposed into a direct signal traveling within the borehole and a reflection signal bearing information about the conductivity distribution outside the borehole. The solution is obtained as a coupled‐mode, multiple‐reflection series accounting for repeated mode reflections at the vertical boundaries in the medium. Each term in the series represents the next higher order reflection in a sequence of multiple reflections; results show two terms are sufficient to reach accuracy acceptable for log modeling.

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Three-Dimensional Reconstruction of Two Forms of the Chaperonin GRO EL

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100180045 ◽

1990 ◽

Vol 48 (1) ◽

pp. 258-259

Author(s):

J.L. Carrascosa ◽

G. Abella ◽

S. Marco ◽

M. Muyal ◽

J.M. Carazo

Keyword(s):

Three Dimensional ◽

The Other ◽

Two Dimensional ◽

Series Method ◽

Three Dimensional Reconstruction ◽

Structural Components ◽

E Coli ◽

Dimensional Reconstruction ◽

Morphogenetic Factors ◽

Tilt Series

Chaperonins are a class of proteins characterized by their role as morphogenetic factors. They trantsiently interact with the structural components of certain biological aggregates (viruses, enzymes etc), promoting their correct folding, assembly and, eventually transport. The groEL factor from E. coli is a conspicuous member of the chaperonins, as it promotes the assembly and morphogenesis of bacterial oligomers and/viral structures.We have studied groEL-like factors from two different bacteria:E. coli and B.subtilis. These factors share common morphological features , showing two different views: one is 6-fold, while the other shows 7 morphological units. There is also a correlation between the presence of a dominant 6-fold view and the fact of both bacteria been grown at low temperature (32°C), while the 7-fold is the main view at higher temperatures (42°C). As the two-dimensional projections of groEL were difficult to interprete, we studied their three-dimensional reconstruction by the random conical tilt series method from negatively stained particles.

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