Microscopic investigations mixtures

As a result of checking a series of dyes, it has been found that the dye Sudan III—IV (mixture) is sorbed defectively by KL-3 preparations. The intensity of dyeing to a reddish-orange color is so strong that it is possible to determine particles of the adhesive in the preparation up to a size of 3 pm (Ref.15>, p. 69). Microscopic investigations of the experimental material have been performed in glueing wound surfaces of different animal organs by the KL-3 adhesive. The results... 

Microscopic investigation of the solid formed when a eutectic freezes indicates that it is a mixture of very fine particles of pure A and pure B, rather than a solid solution of A and B. If a solution that has the eutectic composition is cooled, freezing occurs at a single concentration, just like a pure component. A eutectic can be distinguished from a pure component either by microscopic inspection of the solid or by adding one of the pure components. In the eutectic case, the freezing point of the solution will be increased by this addition, rather than decreased as occurs for a pure substance. 

The identification of phase grading from XRD alone is not possible microscopic methods (Chui and Chan, 2005 Dutoit et al., 1995 Hills et al., 1999 Prakash et al., 2005) are needed to determine the locations of the phases that are identified. It is critical to compare the same active state of the catalyst in XRD and in microscopic investigations, as core-shell structures may be the result of phase segregation during sample preparation and transfer from a metastable statistical mix (Conte et al., 2006 Havecker et al., 2003 Hutchings, 2004 Kiely et al., 1996) into the more stable graded phase mixture (Frenkel et al., 2001 Fu et al., 2005 Hills et al., 1999). 

Association phenomena in dilute solutions of atactic (a) and stereoregular (i,s) PMMA in suitable solvents have been extensively studied in the past. The anomalies observed even in dilute solutions were explained by intermolecular association of complementary sequences of the stereoregular polymer chains, so-called stereocomplex formation. Besides the well known stereocomplex, remarkable effects in solutions of either i- or s-PMMA alone led to the assumption that associated structures can also be formed as a consequence of interactions between sequences of equal tacticity. It has been found that the solvent exhibits a striking influence on the association of PMMA. This paper deals predominantly with rheological investigations of dilute solutions of a-, i- and s-PMMA and their mixtures, as well as investigations on a stereoblock polymer. Results of calorimetric and electron microscopic investigations will be taken into account. 

Within the scope of electron microscopic investigations on structures in high molecular solutions, mixtures between i- and s-PMMA in acetone reveal morphological ordered structures, especially when the ratio s/i is 2 1 by weight (Figure 15). 

Because of their sizes, neither K+ nor Si + can enter into solid solution with the magnetite and so if some silica is present in the iron oxide used, small occlusions of alkali silicates are present as separate phases in the fused catalyst. Microscopic investigations of the milled catalyst showed that whereas the larger particles still contain alkali silicate occlusions, the finer particles consist of a mixture of separate alkali silicate and magnetite particles (20). Hence, the distribution of alkali in the milled, fused catalyst is heterogeneous. During reduction and FT synthesis, however, the alkali does to some extent spread over the catalyst surface ((7), chapter 3). 

The thermal characterization of DOMS-DAT mixture performed in the temperature range between 130 and 180°C reveals an unusual bimodal peak. The formation of the liquid crystalline phase during the curing reaction is assumed to increase of the reaction rate. This fact is sustained by the microscopic investigation... 

As can be seen in TABLE 1, not all substances have a nematic phase but some of these compounds can also be important components of practical mixtures. That means, from an application point of view, it is necessary to characterise those non-nematic or non-liquid-crystalline substances by an effective or virtual dielectric anisotropy. Mainly for this reason, the dielectric properties are usually measured in mixtures, containing the corresponding substances at a fixed concentration, and the value characteristic of the component is obtained by extrapolation. This provides the main reasons for the scatter in the data, some of which can be attributed to the different host mixtures used. In this connection, too, dipole-dipole association is an important factor to make the microscopic investigation of the dielectric property of a nematic phase precise. The extrapolation conditions are noted in TABLE 1 and details can be found in the appropriate references. 

The influence of the lipophilic external phase on the production of xylan-based microparticles by interfacial cross-linking polymerization has been investigated (Nagashima et al., 2008). Three different external phases were investigated a 1 4 (v/v) chloroform cyclohexane mixture, soybean oil, and a medium chain triglyceride, with viscosities below 1, 24, and 52 cP, respectively. It was observed that the use of these different lipid phases results in different macroscopic and microscopic aspects of the system (Figure 10). 

We have recently initiated our investigation of blends by examining the compatibility between our modified polymer sample 4 and poly(methyl methacrylate). Mixtures with a composition of between 10% and 30% of sample 4 yield compatible blends which are transparent under a polarized light microscope, and are characterized by a single Tg. Mixtures richer than 60% of 4 undergo complete phase separation. 

One of the most promising applications of enzyme-immobilized mesoporous materials is as microscopic reactors. Galameau et al. investigated the effect of mesoporous silica structures and their surface natures on the activity of immobilized lipases [199]. Too hydrophilic (pure silica) or too hydrophobic (butyl-grafted silica) supports are not appropriate for the development of high activity for lipases. An adequate hydrophobic/hydrophilic balance of the support, such as a supported-micelle, provides the best route to enhance lipase activity. They also encapsulated the lipases in sponge mesoporous silicates, a new procedure based on the addition of a mixture of lecithin and amines to a sol-gel synthesis to provide pore-size control. 

An unusually extensive battery of experimental techniques was brought to bear on these comparisons of enantiomers with their racemic mixtures and of diastereomers with each other. A very sensitive Langmuir trough was constructed for the project, with temperature control from 15 to 40°C. In addition to the familiar force/area isotherms, which were used to compare all systems, measurements of surface potentials, surface shear viscosities, and dynamic suface tensions (for hysteresis only) were made on several systems with specially designed apparatus. Several microscopic techniques, epi-fluorescence optical microscopy, scanning tunneling microscopy, and electron microscopy, were applied to films of stearoylserine methyl ester, the most extensively investigated surfactant. 

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