Self microscopic techniques

There are macroscopic (uptake measurements, liquid chromatography, isotopic-transient experiments, and frequency response techniques), and microscopic techniques (nuclear magnetic resonance, NMR and quasielastic neutron spectrometry, QENS) to measure the gas diffusivities through zeolites. The macroscopic methods are characterized by the fact that diffusion occurs as the result of an applied concentration gradient on the other hand, the microscopic methods render self-diffusion of gases in the absence of a concentration gradient [67]. 

Since most microscopic techniques measure self-diffusion, whereas the macroscopic techniques generally measure transport diffusion, direct comparisons between the measured diffusivities are not meaningful, except in the... 

On the other hand, molecular chirahty is sometimes expressed at a much larger scale in the morphology of self-assembled fibers. Elongated, fibrous objects such as rods, tapes, or tubes may be helically twisted, coiled, or wound around one another, and therefore exist in a left-handed or a right-handed form. These intriguing shapes can often be simply visualized by microscopic techniques and have fascinated both chemists and physicists. The third section of this chapter aims to illustrate the structural variety of these objects and the extent to which their formation can be altered and their shapes tuned upon changing the experimental conditions. It also gives a perspective of the... 

As described in the Introduction, Pasteur showed beautifully that racemic molecules resolve spontaneously into chiral forms when they crystallize. We call them conglomerates, in which molecules form condensates comprised of only one enantiomer. The condensation into conglomerates can now be observed not only in crystals but in monolayers, fibers, and supramolecules self-assembled in solution [35]. The researches became possible because of the development of microscopic observation techniques at the nanometer scale. However, in crystals we still do not know what kinds of molecules show spontaneous resolution. Hence, observation of chiral resolution in soft matter may provide important information on the general question. 

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