RESP method

Kollman and coworkers take an alternative tack to reducing the effective size of the problem. Rather than eliminating atoms from the fit, essentially reducing the value of their charge to zero, the authors RESP method produced a problem of lower rank by imposing symmetry constraints when available. The RESP approach also incorporates a hyperbolic penalty function into the fit. 

Bayly, C. 1., Cieplak, R, Cornell, W. D., and Kollman, P. A. (1993). A well-behaved electrostatic potential base method using charge restraints for deriving atomic charges the RESP method, /. Phys. Chem. 97, pp. 10269-10280. 

RESP method. Bond lengths and bond angles were constrained to reproduce the optimum geometry from QM calculations. The U parameters were optimized to experimental values of shear viscosity, self-diffusion coefficient, and liquid density. A review on force fields for the simulation of imidazohum-based ionic liquids can be found in [175]. 

The range of systems that have been studied by force field methods is extremely varied. Some force fields liave been developed to study just one atomic or molecular sp>ecies under a wider range of conditions. For example, the chlorine model of Rodger, Stone and TUdesley [Rodger et al 1988] can be used to study the solid, liquid and gaseous phases. This is an anisotropic site model, in which the interaction between a pair of sites on two molecules dep>ends not only upon the separation between the sites (as in an isotropic model such as the Lennard-Jones model) but also upon the orientation of the site-site vector with resp>ect to the bond vectors of the two molecules. The model includes an electrostatic component which contciins dipwle-dipole, dipole-quadrupole and quadrupole-quadrupole terms, and the van der Waals contribution is modelled using a Buckingham-like function. 

The Production Department was not amused, because lower values had been expected. Quality Control was blamed for using an insensitive, unse-lective, and imprecise test, and thereby unnecessarily frightening top management. This outcome had been anticipated, and a better method, namely polarography, was already being set up. The same samples were run, this time in duplicate, with much the same results. A relative confidence interval of 25% was assumed. Because of increased specificity, there were now less doubts as to the amounts of this particular heavy metal that were actually present. To rule out artifacts, the four samples were sent to outside laboratories to do repeat tests with different methods X-ray fluorescence (XRFi °) and inductively coupled plasma spectrometry (ICP). The confidence limits were determined to be 10% resp. 3%. Figure 4.23 summarizes the results. Because each method has its own specificity pattern, and is subject to intrinsic artifacts, a direct statistical comparison cannot be performed without first correcting the apparent concentrations in order to obtain presumably true... 

Yeadon, M., Price, R. and Payne, A.N. (1994). A method for measurement of upper airway mucus secretion in guinea-pigs in vivo. Am. J. Resp. Crit. Care Med. 149, A329. 

Bousquet, J, Tosserard, B., and Medley, H.V., Double-blind parallel group study to compare the long term clinical efficacy and safety of two different methods of administering inhaled fluticasone propionate in chronic severe asthmatic patients, Eur. Resp. J., 8 427S (1995). 

Industrial wastewater may be colored and color removal may be required to comply with regulation. Coque et al. describe how various discoloration methods were studied with standard azo dyes solutions and an industrial wastewater from the paper industry as model systems. The liquids were recirculated between the photochemical discoloration reactor and an at-line spectrophotometer (Suprasil quartz cell, path length 2 or 10mm, resp.). A discoloration yield x was calculated in CIE L a b space, which permitted monitoring the process and determining completion in an easily implemented manner. 

Using the ASTM method of measurement these authors found the max safe (below self-ign) temp of o- and p-xylenes to be 451° and 477°, resp]... 

The consecutive reactions have been investigated by the method of preparative voltammetry, namely by analyzing the product mixture, which is essentially composed of the anodic monomer and dimer independence of working potential or current density resp. Correlating the respective current and mass yields of monomers and dimers with current density allows the kinetic laws governing the selectivities at different anode materials to be obtained. 

The mean primary particle sizes of pigment blacks he in the range 10-100 nm specific surface areas are between 20 and 1000 m2/g. The specific surface area, determined by N2 adsorption and evaluation by the BET method [4.29], is often cited as a measure of the fineness of a black. Blacks with specific surface areas >150 m2/g are generally porous. The BET total specific surface area is larger than the geometric surface area measured in the electron microscope, the difference being due to the pore area resp. the pore volume. 

In Tables 1 and 2 the methods of generation and experimental evidence for the intermediate occurrence of unstable cycloalkynes and methods of synthesis of isolable angle strained cycloalkynes, resp. are given. 

For the cyclization to the 16-membered macrolactone structure of epothilones C and D (= desoxyepothilones A and B, resp. [26]), three different strategies have been used successfully so far (1) Ring-closing olefin metathesis (RCM) between C12 and Cl3. RCM is a comparably new method in total synthesis and underwent enor-... 

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