Systematic Extension

There is the possibility of building up an extensive systematic chemistry of compounds containing boron-nitrogen bonds, analogous to the chemistry of carbon-carbon bonds but the reactivity of the B—bond is much greater than that of the C—C bond, so that we get physical, but not chemical, resemblances between analogous compounds. 

In order to experimentally check the validity of the time-dependent diffusion theory as applied to the closed-can method, extensive systematic investigations of radon exhalation, with carefully controlled parameters, are needed. To the author s knowledge no such investigations have yet been performed. 

Polybrominated Diphenyl Ethers. There is a lack of quantitative data on the photodegradation potential of PBDEs in air, water, and soil in the presence of natural sunlight. No extensive, systematic studies... 

Extensive systematic work over the past decade has established that bile acid derivatives have the ability to form crystalline inclusion compounds with various organic substances [1], The accumulated data tell us two notable things. One is that their inclusion behavior varies from one case to another. The other is that their crystals consist of host-inherent or guest-dependent assemblies with different molecular arrangements and hydrogen-bonding networks. These facts force us to direct our attention to separation engineering accompanied by crystallization and... 

Since 1970s extensive systematic research was done on designing synthetic polymers containing nucleic acid bases [25], Thymine pendant groups were successfully attached to a variety of polymer backbones, including... 

The measurement of At has included extensive systematic tests [1]. These include i) measurement of At to at least 0.0026 /is-1 (350 ppm) in four different gases, ii)... 

For our problem, due to the lack of specific metal-metal potentials for our clusters, general-purpose potentials were used. Specifically, the Extensible Systematic Forcefield (ESFF) [20,21] and the MM+ forcefield [22,23] were used. For these potentials a number of parameters, (not only non-bonded), are used such as bonded and torsional terms, which are calculated from rule-based algorithms. The resulting parameterisation is not expected to be particularly accurate, but allows choice of specifically bonded candidate structures for which the connectivities can be constrained, based on the precursor skeleton, in the energy minimisations. This method has the advantage of retaining chosen structural units and symmetries of the... 

An extensive systematic substitution study of the a-factor CaaX motif has revealed amino acid preferences and restrictions of the yeast CaaX... 

A very extensive systematic review of 21 monoterpenes with geranilane, p-menthane and pinane/camphene skeletons has recently been published by Martin et al. [351]. Data on individual representatives are compiled, together with references on other compounds, in Table 6.14. 

As mentioned in the previous section, the 6-31G basis does not contain polarization functions on hydrogen. No extensive systematic study using such a basis set has been reported. However, results are available for a number of small molecules and they may be used to evaluate the effect that the addition of p functions on hydrogen has on calculated dipole moments. Neumann and Moskowitz33,34 have obtained near Hartree-Fock wave functions for water and formaldehyde. From these studies they conclude that the inclusion of polarization functions on hydrogen results in rather small changes in the calculated dipole moment. However, it should be pointed out, that they added p functions to a split shell basis set and so their conclusions may not apply directly to the 6-31G level of basis. 

Schemes for the classification and intercomparison of the hydraulic characteristics of different estuaries have been devised (see, for example. Dyer, 1973, Chapter 2) and used extensively. Systematic intercomparisons of estuarine sediment systems have not been made, in part because the requisite data have not been gathered. The task of collecting these data is eased once the critical characteristics needed for intercomparison are established. It is suggested that a scheme for the intercomparison of estuarines can be based on the quantities listed in Tables I and IV.

Dinur, U. and Hagler, A.T. (1991) In Reviews in Computational Chemistry, Vol 2 (eds K.B. Kipkowitz and D.B. Boyd) VCH Publishers, New York, p. 99. Discover 3.2 (1995) Extensible Systematic Forcefield, ESFF, A Component of Discover 95, developed and distributed by Molecular Simulations Inc., 9685 Scranton Road, San Diego, CA 92121, USA. 

The most extensive systematic determination of 4f parameters for ions across the lanthanide series is by Carnall et al. (1988, 1989) for lanthanides in LaFs. The 4f free ion parameters are reduced by a few percent in crystals relative to gaseous ions, but do not change very much from one crystalline environment to another. For this reason, the tabulations of Carnall are still used as the starting point for many of the parametrized calculations within the 4f shell. In most cases, the energy level data are not sufficiently complete to unambiguously determine all of the free ion parameter values, so some of the parameters, such as the three-body parameters, r, are often kept fixed at Carnall s values. The determination of exactly which parameters to keep fixed, and which to vary, is usually decided on a case-by-case basis, based upon how many multiplets are covered by the data, and upon the indeterminacies that arise during the fitting process itself. 

Crawford et al. performed an extensive systematic study of the influence of 5CB-substrate interactions on the ordering of liquid crystal molecules at the interface and on the orientational wetting of the system [21,22]. To vary the liquid crystal-substrate interaction, the chain length of the aliphatic acids (C H2n+i-COOH), attached to the walls of Anopore membranes, was varied from n = 5 to n = 20. Based on the experience with lecithine, one would... 

Ca-PSZ is similar to Mg-PSZ, and develops similar microstructures during high-temperature aging. An important factor is the different critical size for unconstrained m —> t transformation, which is approximately 6-10 nm for Ca-PSZ (compared to 25-30 nm for Mg-PSZ). An extensive systematic investigation of this material has been conducted by Garvie et al., who achieved a considerable increase in the strength of the material, from 200 to 650 MPa, simply by ageing it at 1300 °C [182]. 

S. Barlow, A. L. Rohl, S. G. Shi, C. M. Freeman, and D. O Hare,/. Am. Chem. Soc., 118, 7578 (1996). Molecular Mechanics Study of Oligomeric Models for Poly(ferrocenylsilanes) Using the Extensible Systematic Forcefield (ESFF). 

A. M. Schneider and P. Behrens, Chem. Mater., 10,679 (1998). Molecular Mechanics Study on Organometallic Complexes in Crystalline Silica Matrixes Using the ESFF (Extensible Systematic Force Field). 

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