ZIB

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

Modeling the growth and molecular structure of conductive polymers: Application to poly(dialkoxybenzene)s (1997)

Lacroix, J. C. ; Harvard, G. ; Aaron, J. J. ; [et al.]

Springer

Structural chemistry 8 (1997), S. 177-188

add to mindlist on the mindlist

Details

ISSN: 1572-9001

Keywords: Electropolymerization ; frontier orbital modeling ; poly(dialkoxybenzene)s ; conductive polymers

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology

Notes: Abstract A modeling strategy, based on (i) quantum semiempirical calculation of the electronic structure of the successive intermediate oligomers and (ii) evaluation of the activation energy of the successive coupling reactions by use of the frontier orbital model, has been used to study the growth of a wide set of conductive polymers and is illustrated with poly(1,2-dialkoxybenzene) and poly(1,4-dialkoxybenzene) generated by electrochemical oxidation of the corresponding monomer. These monomers have been chosen because they are known to yield polymers of completely different structures. The strategy, which is designed to be as little computer time-consuming as possible, allows us to predict a growth trend in agreement with the structure inferred from spectrochemical experiments. In the case of poly(1,2-dialkoxybenzene) it suggests the formation of a cyclic tetramer as a byproduct detected in small quantities by means of MALDI spectroscopy. This modeling strategy allows one to describe the electronic modifications induced by the growth of a highly conjugated structure. It suggests that oxidation of the successive oligomers at high doping level and quinonic deformation are key factors for the growth of long and regular polymer structures

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02263505

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Determination of a spatial fracture network (1987)

Thomas, A. ; Pineau, A. ; Blin-Lacroix, J. L.

New York, NY [u.a.] : Wiley-Blackwell

International Journal for Numerical and Analytical Methods in Geomechanics 11 (1987), S. 381-390

add to mindlist on the mindlist

Details

ISSN: 0363-9061

Keywords: Engineering ; Engineering General

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Architecture, Civil Engineering, Surveying , Geosciences

Notes: Hydraulic and mechanical properties of rock masses are largely dependent upon the distribution and variation of fracture areas. Consequently, it is essential to develop good models for analysing the spatial geometric characteristics of fracture fields. The latter, however, may be ascertained only by measuring open cuts or boreholes. The most important factor from the analysis of areas is to be able to determine spatial networks. Without an exhaustive and expensive inventory, the classical methods involving measurements of dip and strike do not provide either a correct estimation of fracture orientations in space, or a good estimation of their distribution.At present, automatic analysis of linear traces on large plane areas is used by several authors1,2 and the field strike and dip measurements are applied only for verification purposes. This method of computing spatial networks is especially suitable because of the nature of data so obtained, since it permits various simulations on computed networks. It is based upon classical methods of vector geometry that involve a measurements data matrix and provide a means of solving a double system of equations. Results are the directional spatial fracture densities. The object of this paper is to define the geometric parameters of this problem and the computation method, to present an example and, finally, to conclude with critical comments supported by certain proposals for a variety of applications.

Additional Material: 12 Ill.