Optical families

All naturally occurring amino acids belong to which optical family ... 

The prefix "D" tells us that D-ribose belongs to the same optical family as D-glyceraldehyde. The other stereoisomer, L-ribose, would be related to L-glycer-aldehyde. Note that the symbols D and L refer to configuration, and not to sign of rotation. 

Hornyak G L and Martin C R 1997 Optical properties of a family of Au-nanoparticle containing alumina... 

Several gemstone species occur in various colors, depending on the presence of impurities or irradiation-induced color centers. Examples are the beryl, comndum, and quart2 families. Quart2 has poor optical properties (RI = 1.55, DISP = 0.013), but becomes of gemological interest when it exhibits attractive colors. Any material can have its color modified by the addition of various impurities synthetic mby, sapphires, and spinel are produced commercially in over 100 colors (2). Synthetic cubic 2irconia has been made in essentially all colors of the spectmm (11), but only the colorless diamond imitation is produced commercially in any quantity. 

Gitronellol Manufacture. CitroneUol is found widely in nature and in both optically isomeric forms. Prior to the development of synthetic citroneUol, this alcohol was obtained from certain oils of the Kosaceae family or by hydrogenation of citroneUal isolated from citroneUa oil. CitroneUol has a floral odor resembling that of roses. 

Shikonin [517-89-5] (Cl 75535) occurs as an acetyl derivative in the Japanese shikone, Uthospermum eTythrorhi n another member of the Boraginaceae family. It is the (R)-optical isomer of alkannin (66). Tissue cultures of E. eythrorhi n are used in Japan to manufacture shikonin mainly for cosmetic use (67). Both alkannin and shikonin are mordant dyes producing violet to gray colors on fabrics. In Japan, shikonin was used to dye fabrics a color known as Tokyo Violet. Shikalkin [54952-43-1] the racemate (11), has been synthesized (68). 

The key innovations in turning optical waveguides (fibres) into a successful commercial product were made by R.D. Maurer in the research laboratories of the Corning Glass Company in New York State. This company was also responsible for introducing another family of products, crystalline ceramics made from glass precursors - glass-ceramics. The story of this development carries many lessons for... 

Spectral Gamma Ray Log. This log makes use of a very efficient tool that records the individual response to the different radioactive minerals. These minerals include potassium-40 and the elements in the uranium family as well as those in the thorium family. The GR spectrum emitted by each element is made up of easily identifiable lines. As the result of the Compton effect, the counter records a continuous spectrum. The presence of potassium, uranium and thorium can be quantitatively evaluated only with the help of a computer that calculates in real time the amounts present. The counter consists of a crystal optically coupled to a photomultiplier. The radiation level is measured in several energy windows. 

Tantalum and niobium are added, in the form of carbides, to cemented carbide compositions used in the production of cutting tools. Pure oxides are widely used in the optical industiy as additives and deposits, and in organic synthesis processes as catalysts and promoters [12, 13]. Binary and more complex oxide compounds based on tantalum and niobium form a huge family of ferroelectric materials that have high Curie temperatures, high dielectric permittivity, and piezoelectric, pyroelectric and non-linear optical properties [14-17]. Compounds of this class are used in the production of energy transformers, quantum electronics, piezoelectrics, acoustics, and so on. Two of... 

Since niobates and tantalates belong to the octahedral ferroelectric family, fluorine-oxygen substitution has a particular importance in managing ferroelectric properties. Thus, the variation in the Curie temperature of such compounds with the fluorine-oxygen substitution rate depends strongly on the crystalline network, the ferroelectric type and the mutual orientation of the spontaneous polarization vector, metal displacement direction and covalent bond orientation [47]. Hence, complex tantalum and niobium fluoride compounds seem to have potential also as new materials for modem electronic and optical applications. 

Crystals with one of the ten polar point-group symmetries (Ci, C2, Cs, C2V, C4, C4V, C3, C3v, C(, Cgv) are called polar crystals. They display spontaneous polarization and form a family of ferroelectric materials. The main properties of ferroelectric materials include relatively high dielectric permittivity, ferroelectric-paraelectric phase transition that occurs at a certain temperature called the Curie temperature, piezoelectric effect, pyroelectric effect, nonlinear optic property - the ability to multiply frequencies, ferroelectric hysteresis loop, and electrostrictive, electro-optic and other properties [16, 388],... 

Currently, these tests are of no practical value to the designer and the only approach to the problem of scratch, mar, and abrasion resistance is to simulate actual performance needs. For optical purposes, a cast sheet in the allyl family of plastics known as CR39 has been used as a standard of comparison in evaluating scratch and mar resistance of a material. The CR39 is used for eye lenses and other optical products where the advantages of plastics are a consideration. Coatings have been developed for polycarbonate, acrylics, and other plastics that dramatically improve the scratch and mar resistance of these materials. 

In the design of MOEMS components, various parameters have to be tuned. These parameters differ according to the functionality of the component. We will consider two different family of devices, programmable slits for Multi-Object Spectroscopy, including Micro-Mirror Arrays (MMA) and Micro-Shutters Arrays (MSA), and Micro-Deformable Mirrors (MDM) for Adaptive Optics systems. 

Extensive structural, optical, and electronic studies on the chalcopyrite semiconductors have been stimulated by the promising photovoltaic and photoelectrochem-ical properties of the copper-indium diselenide, CuInSe2, having a direct gap of about 1.0 eV, viz. close to optimal for terrestrial photovoltaics, and a high absorption coefficient which exceeds 10 cm . The physical properties of this and the other compounds of the family can be modulated to some extent by a slight deviation from stoichiometry. Thus, both anion and cation deficiencies may be tolerated, inducing, respectively, n- and p-type conductivities a p-type behavior would associate to either selenium excess or copper deficiency. 

---