Search parameter field

The names of these search parameter fields are always composed of the respective search code of the superfield code, a dot and the search code for the parameter. Parameter fields must always be searched in combination with the section title using the P-operator (P = paragraph). Thus you make sure, that the retrieved data are related to each other and do belong together. 

Similarly, in the polymer field one would not wish as a response to an enquiry about the copolymerisation of acrylonitrile AND butadiene a text in which the use of EITHER acrylonitrile OR butadiene is described. If in such areas the logical concept relations are not available as restrictive search parameters, then the noise in the retrieval responses can easily become intolerably large in the course of the years. 

A large number of physical-chemical properties depend on several parameters, e.g. temperature and/or pressure. In order to take these conditions into account and make them searchable, the specific search and display fields - e.g. enthalpy of combustion (HCOM) - are divided into parameter fields, which can only be searched. The case of enthalpy of combustion shows these parameter fields ... 

The numeric search is effected analogously to those in Beilstein (Sect. 7.10.3). Therefore Fig. 167 shows a search concerning magnetic susceptibility within a defined temperature range. The parameter fields must be connected with the main search field via the P-operator to look for values and parameters within one entry. 

In the wide field of applications, a visibility level VL = 3 - 60 is recommended. For our recognition task, we are obliged to take into account that our random conditions are far from the experimental conditions of the basic researches (Young test person with a high visus under ideal environmental conditions) [4]. Furthermore in our case we have a more difficult visual searching task. Parameter variations as the increase of presentation time from 0,2 to 1.0 s. and the detection propability from 50% to 100% are taken into account [5] In spite of the gliding variations of the parameters as well as the visibility level, for simplification let us assume VL = 10 as minimum requirement. 

The molecular mechanics force fields available include MM+, OPLS, BIO+, and AMBER. Parameters missing from the force field will be automatically estimated. The user has some control over cutoff distances for various terms in the energy expression. Solvent molecules can be included along with periodic boundary conditions. The molecular mechanics calculations tested ran without difficulties. Biomolecule computational abilities are aided by functions for superimposing molecules, conformation searching, and QSAR descriptor calculation. 

There are different variants of the conjugate gradient method each of which corresponds to a different choice of the update parameter C - Some of these different methods and their convergence properties are discussed in Appendix D. The time has been discretized into N time steps (f, = / x 8f where i = 0,1, , N — 1) and the parameter space that is being searched in order to maximize the value of the objective functional is composed of the values of the electric field strength in each of the time intervals. 

Here (j is the CG update parameter. In the above equations, e = e (tj) o vector notation for the discretized electric field strength, = g (fj) o objective functional J with respect to the field strength (evaluated at a field strength of e t) and dk = d (t ) o search direction at the feth iteration. The time has been discretized into N time steps, such as that tj=jx )t, where j = 0,1,2, , N. Different CG methods correspond to different choices for the scalar (j. ... 

The final part is devoted to a survey of molecular properties of special interest to the medicinal chemist. The Theory of Atoms in Molecules by R. F.W. Bader et al., presented in Chapter 7, enables the quantitative use of chemical concepts, for example those of the functional group in organic chemistry or molecular similarity in medicinal chemistry, for prediction and understanding of chemical processes. This contribution also discusses possible applications of the theory to QSAR. Another important property that can be derived by use of QC calculations is the molecular electrostatic potential. J.S. Murray and P. Politzer describe the use of this property for description of noncovalent interactions between ligand and receptor, and the design of new compounds with specific features (Chapter 8). In Chapter 9, H.D. and M. Holtje describe the use of QC methods to parameterize force-field parameters, and applications to a pharmacophore search of enzyme inhibitors. The authors also show the use of QC methods for investigation of charge-transfer complexes. 

Find the structure parameters x and the properties y of a given compound at room temperature and pressure. What are the properties of the compound at elevated or lowered temperatures and pressures, as well as of other environmental variables, such as electromagnetic field and solar radiation, so that this search can be written as y = f x, T, P)1... 

Chemical Analysis of Extracts. The extracts were analyzed by capillary column GC-MS for OCs, TAAPs, and PAHs (see the list on page 313). The GC-MS parameters used at the two laboratories are shown in Table II. The identification and quantitation were all done by using automatic routines based on a mass spectra library created from authentic standards of the selected compounds. Compounds were located by searching the reconstructed ion chromatogram for each library entry within a narrow retention time window relative to the internal standard (anthracene-dio or phenanthrene-dio). Quantitation was achieved by comparison of characteristic ion areas in the field samples with ion areas of the internal standard. These ion areas were normalized by response factors established by comparison of ion ratios of a standard mixture of all 66 analytes at a concentration of 2.5 ng//zL. 

We randomly perturb the ground state and evolve the perturbation with a given wave vector k in time numerically, searching for any exponential increase of its amplitude which would be a signature of the instability. An example of such a perturbation is presented in Fig. 21. For all velocity field models, the parameter space... 

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