How many "e"s can you find in:
Notes: During the last decade modern preparative and structural methods have led to novel and often unexpected oligomeric and polymeric main group element-sulfur compounds having remarkable bonding and structural properties and reactivities. Examples of important new developments in this area are: the discovery of boron sulfides B8S16 and (BS2)n and of ion-conducting air-stable thioborates with tetrahedrally coordinated boron; the successful use of boron sulfides in organic and inorganic syntheses; the preparation of different homologous series of molecular polynuclear thio- and selenoanions of Ga, In, Si, Ge and Sn, and of new polynuclear sulfide- and selenide-halides of Si and Ge as interesting reagents for inorganic and organic reactions; the synthesis of argyrodite(Ag8GeS6)-like phases with remarkable solid-state properties; and the characterization of the S—H…S type hydrogen bridge in thiocarbonic acid and thiophosphinic acids, which is of importance for an understanding of certain interactions in sulfur-containing biomolecules.
Notes: Photochemical hole burning is a special type of saturation spectroscopy in the optical domain having many analogies with NMR methods. The holes, which are burnt with laser irradiation, appear as small indentations in the absorption spectra of dye molecules which are doped into a polymer or glass in minute concentrations. Based on their narrow line width, photochemical holes can be regarded as highly sensitive spectroscopic probes. They can be used to detect small perturbations of the system by external parameters, giving rise to line-shifts and broadenings. Besides the many well documented, spectroscopic applications of hole burning, it may offer interesting future developments for the spectroscopy of biomolecules and for high-density data storage.
Notes: Oligomers belong to the gray area between low molecular weight chemistry and macromolecular chemistry. Although they represent an undesirable “natural impurity” in fiber-forming polycondensates, they serve as useful model compounds for the corresponding polymers in fundamental research. Whereas for many years new classes of oligomers were being made preparatively accessible and the isolation of higher oligomers in pure form was being pursued, at the present time the emphasis is on analysis. By a combination of classical chemical and instrumental methods of analysis from polymer and organic chemistry, the identification of oligomers of unknown structure, the analytical control of their synthesis and the determination of their content in technical polymers has meanwhile become a routine task.
Mark, Hermann F.
Notes: The substantial rapid growth of synthetic polymers - plastics, man-made fibers, films, rubbers, and coatings - which continued unabated over many years, suffered a severe setback for the first time in 1973-1974 followed by another in 1980. A major cause of these reverses was the changed situation with respect to raw materials and energy. For industrial polymer research, in particular, this presents a fresh challenge with considerably changed priorities. The individual ways of meeting this challenge are highlighted and illustrated by examples: the search for alternative raw material sources for monomers; the development of economic methods for production and processing of polymers; the recycling of polymers; and finally the development of new raw material-saving and energy-saving technologies based on the use of polymers. In the future, the applications of polymers to new technologies such as communication- and information-systems or biotechnology will join the traditional uses. But the efforts required in research and development to achieve this demand wide-ranging interdisciplinary cooperation on an even greater scale than hitherto.
Notes: Against the background of increasing demand and limited availability of fossil, non-regenerative fuel reserves and resources, ways are indicated of ensuring future supplies of raw materials and energy. The ambivalence of petroleum, natural gas, and coal in the energy and chemical sectors is demonstrated and opportunities for the gradual separation of their dual function are indicated. Taking into account the time factor, the necessary restructuring processes are analyzed critically with respect to their impact on the raw material-polymer relationship.
user
The passage contains four hundred and twenty-nine "e"s.
assistant