A Long History

Reference compound Frequency MHz ( H = 100 MHz) Receptivity D relative to H = 1.00 Receptivity D relative to C = 1.00 Magnetogyric ratio, radio s Nuclear quadropole moment, barn 

Characteristic X-radiation Z Element Ka, keV X-ray radiation absorbed by the element Incoming radiation energy Absorption coefTicient p (enf /g)  

Neutron absorption Thermal neutron capture cross section 0.0034 barns 

Knowledge about carbon as a chemical element was developed far later, beginning in the 18 century. In the middle of that century Joseph Black in Scotland showed that when charcoal is burned a gas is formed, the properties of which are different from those of air. This gas, carbon dioxide, was for a long time designated/ixed air. The difference between graphite and carbon was elucidated only with great difficulty, in connection with the century s important work about iron and steel. This is described in Chapter 8 Iron. 

In the same century it was clarified that diamond is a form of carbon. In 1772 Lavoisier and a group round him placed a diamond in a glass case and ignited it with a big burning glass. They collected the gas above mercury, added slaked lime, and got an obvious precipitation of calcium carbonate. The burning glass had heated the air, which had oxidized the diamond carbon to carbon dioxide. At the start of 19 centu- 

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This subject has a long history and important early papers include those by Deijaguin and Landau [29] (see Ref. 30) and Langmuir [31]. As noted by Langmuir in 1938, the total force acting on the planes can be regarded as the sum of a contribution from osmotic pressure, since the ion concentrations differ from those in the bulk, and a force due to the electric field. The total force must be constant across the gap and since the field, d /jdx is zero at the midpoint, the total force is given the net osmotic pressure at this point. If the solution is dilute, then... 

The treatment of equilibrium solvation effects in condensed-phase kmetics on the basis of TST has a long history and the literature on this topic is extensive. As the basic ideas can be found m most physical chemistry textbooks and excellent reviews and monographs on more advanced aspects are available (see, for example, the recent review article by Tnihlar et al [6] and references therein), the following presentation will be brief and far from providing a complete picture. 

This review has covered many of the essential features of the physical chemistry of nanocrystals. Rather than provide a detailed description of the latest and most detailed results concerning this broad class of materials, we have instead outlined the fundamental concepts which serve as departure points for the most recent research. This necessarily limited us to a discussion of topics that have a long history in the community, leaving out some of the new and emerging areas, most notably nonlinear optical studies [152] and magnetic nanocrystals [227]. Also, the... 

The next step towards increasing the accuracy in estimating molecular properties is to use different contributions for atoms in different hybridi2ation states. This simple extension is sufficient to reproduce mean molecular polarizabilities to within 1-3 % of the experimental value. The estimation of mean molecular polarizabilities from atomic refractions has a long history, dating back to around 1911 [7], Miller and Sav-chik were the first to propose a method that considered atom hybridization in which each atom is characterized by its state of atomic hybridization [8]. They derived a formula for calculating these contributions on the basis of a theoretical interpretation of variational perturbation results and on the basis of molecular orbital theory. 

The use of group contribution methods for the estimation of properties of pure gases and Uquids [20, 21] and of phase equilibria [22] also has a long history in chemical engineering. 

The focus of this section is the emission of ultraviolet and visible radiation following thermal or electrical excitation of atoms. Atomic emission spectroscopy has a long history. Qualitative applications based on the color of flames were used in the smelting of ores as early as 1550 and were more fully developed around 1830 with the observation of atomic spectra generated by flame emission and spark emission.Quantitative applications based on the atomic emission from electrical sparks were developed by Norman Lockyer (1836-1920) in the early 1870s, and quantitative applications based on flame emission were pioneered by IT. G. Lunde-gardh in 1930. Atomic emission based on emission from a plasma was introduced in 1964. 

Although ABS resins have a long history by industry standards, the products are anything but mature. ABS resins and blends are, and are expected to remain, the engineering thermoplastics of choice for a wide array of markets. 

The pomegranate alkaloids, pelletierine (46) and pseudopelletierine (48) as well as minor accompanying bases, have a long history as salts of tannic acid as an anthelmintic mixture for intestinal pinworms (see Antiparasitic AGENTS, ANTHELMINTICS). The alkaloids themselves (as the taimates) are obtained from pomegranate tree (Punkagranatum L.) root bark and are among the few bases named after an individual (P. J. Pelletier) rather than a plant. 

Konjac flour, derived from the konjac plant tuber, has a long history of use in the Ear East, but is a newcomer to the United States. It reacts with many starches to enhance the viscosity of both, and is used in gels that are stable in boiling water. 

A special class of stones are the precious and semiprecious gemstones, with a long history of use in decorations and jewelry. Especially in the Far East and pre-Columbian America, jade was used extensively for carving ceremonial and luxury items. Jade encompasses two different minerals quite similar... 

Hydrocarbons were first used in the field of medicine by the Romans. Bitumen was used in ancient Mesopotamia as mortar for bricks, as a road constmction material, and to waterproof boats. Arabia and Persia have a long history of producing oil. 

Most by-product acetylene from ethylene production is hydrogenated to ethylene in the course of separation and purification of ethylene. In this process, however, acetylene can be recovered economically by solvent absorption instead of hydrogenation. Commercial recovery processes based on acetone, dimetbylform amide, or /V-metby1pyrro1idinone have a long history of successfiil operation. The difficulty in using this relatively low cost acetylene is that each 450, 000 t/yr world-scale ethylene plant only produces from 7000 9000 t/yr of acetylene. This is a small volume for an economically scaled derivatives unit. 

Spectra. The abiHty to consult collections of standard spectra is cmcial in the analysis of unknown compounds. A long history of data collection efforts has been aimed at these appHcations. Among the best known of the pubHshed handbooks are the Sadtkr Spectral Data Sheets which include ir,... 

The soap of modified rosin has a long history as an emulsifier for the polymerization of styrene—butadiene mbber. The rosin soap remains in the mbber after polymerization and increases the tack between the pHes of mbber required in the manufacture of tires. 

Ion-selective electrodes and amperometric ceUs have had a long history of success in a wide variety of appHcations (8,9). A microelectronics-inspired revolution is also occurring in these devices, brought about by the advent of photoHthographicaHy defined arrays of microelectrodes on planar substrates... 

Pharmaceutical Applications. Sucrose has a long history in the manufacture of pharmaceuticals. It imparts body to symps and medicinal hquids and masks unpleasant tastes. Sucrose also functions as a diluent to control dmg concentrations in medicines, as an ingredient binder for tablets, and to impart chewiness to the latter. Sustained-release medications and protective tablet glazes are prepared using sucrose (41). Sucrose-based sugar pastes are used to promote wound healing (58). 

Metastable growth of diamond takes place from gases rich in carbon and hydrogen at low pressures where diamond would appear to be thermodynamically unstable. The subject has a long history, beginning with work in the United States and Russia as early as 1962 (30—32) but not achieving widespread interest and acceptance until about 1986 after successful work in Japan. 

Latex Adhesive Applications. Polychloroprene latex adhesives have a long history of use in foil laminating adhesives, facing adhesives, and constmction mastics. Increasingly stringent restrictions on the emission of photoreactive solvents has heightened interest in latex compounds for broader apphcations, particularly contact bond adhesives. Table 10 makes a general comparison of solvent and latex contact bond adhesives (158). 

Semibatch hydrogenation of edible oils has a long history and a well-estabhshed body of prac tice by manufacturers and catalyst suppliers. Problems of new oils, new specifications, new catalyst poisons,... 

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