Homogeneous Having properties

The chapters in this volume illustrate how molecular concepts underlie catalysis. They illustrate how modern concepts of biology are influencing catalysis and catalyst discovery how concepts of homogeneous and surface catalysis have merged (a theme that is evident in the preceding several volumes of the Advances), exemplified by dendrimer catalysts that have properties of both molecules and surfaces and how concepts of molecular catalysis by bases have influenced the development of new solid-base catalysts and fundamental understanding of how they function. 

Few examples of the homogeneous diblock-incompatible homo-polymer behavior have been reported. One that has received considerable attention is the system polystyrene-poly-a-methylstyrene (2). Block copolymers of styrene and a-methylstyrene exhibit a single loss peak in dynamic experiments (2,3) and have been shown to be thermorheologi-cally simple (4) hence they are considered to be homogeneous. Mechanical properties data on these copolymers also has been used to validate interesting extensions of the molecular theories of polymer viscoelasticity (2,3,4). 

Two or more substances—elements, compounds, or both—can combine physically to produce a mixture. A mixture can be separated into its components by physical means. Mixtures are physical combinations of substances that have properties related to those of their components but that do not have definite compositions. They can be either heten eneons or homc eneons mixtures. In heterogeneous mixtures, two or more different types of matter can be seen to be present with the naked eye or a good optical microscope. Homogeneous mixtures, also called solutions, look alike throughout, even under a microscope. 

These Fe proteins have been purified to homogeneity (5,23,24) they are j2 dimers containing approximately 4Fe and 4S atoms and have properties very similar to those of the Fe proteins of Mo nitrogenases (Table I). 

The poles discussed in Chapter 4 belong to the category of space-independent objects, that is, points or homogeneous bodies. Here, we examine the case of poles that have properties dependent on space. 

Multielectron redox reactions at the interface between two immiscible liquids were first investigated by Bell [8]. This approach was later extended to redox and hydrolysis reactions catalyzed by enzymes [2,9-11], photosynthetic pigments [12], metal complexes of porphyrins [13-15], and submitochondrial particles [16], as well as in systems with an extended surface such as microemulsions [12], vesicles and reversed micelles [17]. Enzymes and pigments embedded in a hydrophihc-hydrophobic interface have properties similar to their functional state in a membrane. For instance, certain enzymes can be highly active at the interface, but virtually inactive in a homogeneous medium. The interface between two immiscible liquids with immobilized photosynthetic pigments can also serve as a simple... 

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