A theoretical framework for general design of two-materials composed diffractive fresnel lens

Near 100% of diffractive efficiency for diffractive optical elements (DOEs) is one of the most required optical performances in broadband imaging applications. Of all flat DOEs, none seems to interest researchers as much as Two-Materials Composed Diffractive Fresnel Lens (TM-DFL) among the most promising flat DOEs. An approach of the near 100% of diffractive efficiency for TM-DFL once developed to determine the design rules mainly takes the advantage of numerical computation by methods of mapping and fitting. Despite a curved line of near 100% of diffractive efficiency can be generated in the Abbe and partial dispersion diagram, it is not able to analytically elaborate the relationship between two optical materials that compose the TM-DFL. Here, we present a theoretical framework, based on the fundaments of Cauchy's equation, Abbe number, partial dispersion, and the diffraction theory of Fresnel lens, for obtaining a general design formalism, so to perform the perfect material matching between two different optical materials for achieving the near 100% of diffractive efficiency for TM-DFL in the broadband imaging applications.

PADRE MARTINI, GAETANO GASPARI AND THE ‘PAGLIARINI COLLECTION’: A RENAISSANCE MUSIC LIBRARY REDISCOVERED

A substantial collection of Cinque- and Seicento prints lies hidden in the Museo Internazionale e Biblioteca della Musica in Bologna. Practically unknown to scholars, at 274 titles it is among the largest collections dating from the Renaissance. The fortunate series of events that account for its survival are retraced, beginning with its formation c. 1580 and its purchase by Padre Giambattista Martini (1706–84) from the Pagliarini booksellers in Rome with the aid of Girolamo Chiti, and ending with its partial dispersion in the nineteenth century. A complete index of the collection is included, together with a list of the unica.

Partial Dispersion

In this chapter, we discuss the partial dispersion of manufacturing facilities and offshore production. It is better to locate most suppliers and manufacturers in close proximity at the beginning of the life cycle. However, as time passes, companies start locating assembly facilities in the other advanced countries for sales promotion and, sometimes, cost cutting. It becomes desirable for the manufacturers to avoid trade friction and to penetrate foreign markets quickly. The standardization of the product including the modularity of the parts makes it possible to do so. The partial dispersion at the standardized stage of the VCR industry is demonstrated in the latter part of this chapter.

A classification of soil aggregates based on their coherence in water

Soil aggregates have been divided into seven classes by observing the coherence of the clay fraction after reacting aggregates with water. The reactions used were: immersion of dry aggregates in water, immersion of wet remoulded aggregates in water, and suspension of aggregates in water. One further class was distinguished by the presence of carbonate. Illite and montmorillonite clays were modified so as to exhibit the physical properties of some of the aggregate classes. The results with the clays were then used to explain the characteristic properties of aggregates derived from a wide variety of soils in the various classes. For example, class 2 aggregates show partial dispersion when placed, dry, in water. The minimum percentage of exchangeable sodium present in aggregates of this class was equal to that required for dispersion of the dry Na/Ca-clays immersed in water. Examples are given of where the detection of dispersion from aggregates can be useful in the field. As only simple tests are used, the proposed method of classification can be easily carried out under field conditions.