Morphological Questions

Important morphological questions about miscible blends in which one or both components have crystallized concern the nature of the overall crystalline texture and the location of the amorphous material. A number of recent publications have sought answers to these questions for particular systems. Early microscopy studies showed that noncrystallizable diluents increased the coarseness of the spherulites of the crystallizable components (21,22) however, more recent scattering experiments have been able to determine more detailed information. 

Imaging of Surfaces—Analysis of Surface Morphology. Several important techniques can help answer the question what does the surface look like This question is often the first one to be posed ia the characterization of a new surface or iaterface. Physical imaging of the surface is necessary to distinguish the relevant features important for understanding the whole surface and is essential for accurate iaterpretation of data from other surface analysis techniques which might later be appHed to a more limited region of the surface or iaterface. 

In the analysis of crystal growth, one is mainly interested in macroscopic features like crystal morphology and growth rate. Therefore, the time scale in question is rather slower than the time scale of phonon frequencies, and the deviation of atomic positions from the average crystalline lattice position can be neglected. A lattice model gives a sufiicient description for the crystal shapes and growth [3,34,35]. 

Kohli et al. [27], for instance, showed that the tensile modulus of a highly drawn PC-TLCP composite could be modeled effectively by the simple additivity rule of mixtures, while the compression molded composite samples with a spherical TLCP morphology had moduli according to the inverse rule. In both cases, the tensile modulus of the TLCP (Ei,c) itself was assumed to be a constant value determined from a tensile test of the pure TLCP samples. But whether or not the dispersed TLCP fibers and deformed droplets have the same modulus as the bulk TLCP samples remains a question. 

Transmission electron microscopic observaiion reveals various morphologies of precipitates depending upon the constituents and composition of an alloy system, history of heat treatments etc. Typical examples are spherical precipitates found in Nl-Cr-Al system and cuboidal precipitates in Fe-Mo system [1]. The first question raised is what determines the shape of a precipitate. 

There have been questions raised as to the suitability of using nucleation to explain, for example, the morphology or concentration behaviour. However, Toda... 

Recent demands for polymeric materials request them to be multifunctional and high performance. Therefore, the research and development of composite materials have become more important because single-polymeric materials can never satisfy such requests. Especially, nanocomposite materials where nanoscale fillers are incorporated with polymeric materials draw much more attention, which accelerates the development of evaluation techniques that have nanometer-scale resolution." To date, transmission electron microscopy (TEM) has been widely used for this purpose, while the technique never catches mechanical information of such materials in general. The realization of much-higher-performance materials requires the evaluation technique that enables us to investigate morphological and mechanical properties at the same time. AFM must be an appropriate candidate because it has almost comparable resolution with TEM. Furthermore, mechanical properties can be readily obtained by AFM due to the fact that the sharp probe tip attached to soft cantilever directly touches the surface of materials in question. Therefore, many of polymer researchers have started to use this novel technique." In this section, we introduce the results using the method described in Section 21.3.3 on CB-reinforced NR. 

So if ACh is involved in memory function, what does it do Any attempt to answer that question has to follow some consideration of how memory is thought to be processed. Many neuroscientists believe that memory is achieved by changes in the strength of synaptic connections (activation) between neurons and that increases in such synaptic activity somehow reinforce the pattern of neuronal activity during the memorising of an event so that it can be more easily restored later. One form of such plasticity is longterm potentiation (LTP), which has been mostly studied in the hippocampus where, as in other areas associated with memory, there is the appropriate complex synaptic morphology. 

QUESTION What we really need is to do some morphological studies with something that is very selective for those particular neurons, and I agree with you that that is something we need to strive for. Are you doing that at the Addiction Research Center ... 

ANSWER Yes. We have very carefully evaluated that question and Dr. O Hearn is a great skeptic who is forcing us to look at it very closely. We are finding that the large varicosity fibers that are left are identical in distribution, morphology, and density to those present in the normal fibers. The damaged fibers are of a completely different nature they are 10 times... 

Having said this, it was felt therefore that there is a need for a book addressing analysis and characterisation of polymers from the point of view of what we wish to call the primary analytical question. Many excellent textbooks and reference works exist which address one or more individual analytical techniques, see, for example, references [1-10]. These books form the basis of the knowledge of the technique expert. They also contain many excellent and varied examples on successful applications of analytical techniques to polymer analysis and characterisation. There are also books which address the multitude of analytical techniques applied in polymer analysis, see, for example, references [11-24], However, a synthetic chemist may wish to know the constitution of his/her polymer chain, a material scientist may want to find out the reasons why a fabricated sample had failed. What technique is best or optimal to study chain constitution will depend on the situation. Polymer failure may result from morphological features, which needs to be avoided, a contaminant, a surface property degradation, etc. When a sample has been processed, e.g., a film blown, molecular orientation may be the key parameter to be studied. A formulation scientist may wish to know why an additive from a different supplier performs differently. It is from such points of view that polymer analysis and characterisation is addressed in this book. 

At the end of 2003, new research results led to sensational headlines Minerals Cooked Up in the Laboratory Call Ancient Microfossils Into Question was the title chosen by Richard A. Kerr for his article in Science dealing with synthetically prepared silicate carbonates. Their microstructures show morphologies which look exactly like those of filaments which had been assigned as cyanobacterial microfossils of the Precambrian Warrawoona chert formation in western Australia. The synthetic structures consist of silicate-encapsulated carbonate crystals, and in part have a helically twisted morphology reminiscent of biological objects. Simple... 

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