Field-step focusing

The thin-film separator can also be operated in a binary mode called field-step focusing (89) (Figure 6). 

Wagner, H. Kessler, R. "Free-flow field-step focusing a new method for preparative protein isolation" In Electrophoresis 83. Stathakos, D., Ed. W. de Gruyter Berlin, Germany, 1983, pp. 303-312. 

Continuous isoelectric focusing and field step electrophoresis... 

Fig. 8. Free-Flow Electrophoresis. Schemes of the following techniques are presented A, zone electrophoresis B, isotaphoresis C, isoelectric focusing and D, field step electrophoresis. The top panels show the inlet system, the lower panels illustrate the purification of components and the outlet system. S - sample to be separated LE, TE leading and terminating electrolytes, respectively A, C. D are three ampholytes focusing in pH profile.

The advent of ISO 9000 certification has helped bring the quality issue to a focus. While ISO 9000 emphasis is on documentation of methodology and performance to the documented methods, the discipline that results is a direct step toward improvements in reliability. Out of this seems to come a goal of continuous improvement. This is a sharp contrast to the high growth era that took place in the early 1980s when poor quality on the part of the equipment suppliers was a significant factor in the lack of reliability at the field operation level. 

The last twenty years have seen a rapid development of surface physics. In particular, the properties of clean perfect surfaces (with two-dimensional periodicity) are henceforth well known and understood. In recent years, the focus has been put onto surfaces with defects (adatoms, steps, vacancies, impurities...) which can now be investigated experimentally due either to the progress of old techniques (field ion microscopy or He diffraction, for instance) or to the rapid development of new methods (STM, AFM, SEXAFS...). 

Molecular mechanics is the simplest and the most commonly used molecular modelling technique. It focuses on the low energy structures of molecules which correspond to energy minima in the classical force field used to represent the molecule [44]. A typical molecular mechanics study consists of the following steps [45] ... 

Fuel industry is of increasing importance because of the rapidly growing energy needs worldwide. Many processes in fuel industry, e.g. fluidized catalytic cracking (FCC) [1], pyrolysis and hydrogenation of heavy oils [2], Fischer-Tropsch (FT) synthesis [3,4], methanol and dimethyl ether (DME) synthesis [5,6], are all carried out in multiphase reactors. The reactors for these processes are very large in scale. Unfortunately, they are complicated in design and their scale-up is very difflcult. Therefore, more and more attention has been paid to this field. The above mentioned chemical reactors, in which we are especially involved like deep catalytic pyrolysis and one-step synthesis of dimethyl ether, are focused on in this paper. 

Photochemical reactions occur when a gas, a solution, or a solid mixture of chemicals absorbs light to produce an excited state, which further reacts generating different reaction products. Part of the excited-state particles might not convert into new species, but rather revert to the ground-state species. The research field of heterogeneous photochemistry is focused toward the investigation of each of the above-mentioned steps and elucidation of their mechanism and kinetics. 

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