Richardson model

Because the general features of the Faulkner-Richardson model are representative and convey a simple physical picture, and it is the only model that has been extensively and fairly successfully applied to the interpretation of the vibronic spectra of Cs2NaLnCl6 systems, it will be described in slightly... 

Thermal electron emission from a solid (dark current in a photocathode) can be modeled in various degrees of complexity and full models for either classical or NEA emitters [5.139,140] require a fair amount of detail. In simplified form we can consider initially the limit of treating the substance as a perfect electron source (an electron black body ). Here all electrons which are thermally excited to energy greater than the surface barrier (work function or electron affinity) are emitted, and each emitted electron is assumed to be instantly replaced by an electron from the bulk. This is roughly the Richardson model, which applies fairly well to a metal. The dark current computed from this model is an upper limit to emission of a real device. 

Figure 14.15 Stmcture of the SI fragment of chicken myosin as a Richardson diagram (a) and a space-filling model (b). The two light chains are shown in magenta and yellow. The heavy chain is colored according to three proteolytic fragments produced by trypsin a 25-kDa N-terminal domain (green) a central 50-kDa fragment (red) divided by a cleft into a 50K upper and a 50K lower domain and a 20-kDa C-terminal domain (blue) that links the myosin head to the coiled-coil tail. The 50-kDa and 20-kDa domains both bind actin, while the 25-kDa domain binds ATP. [(b) Courtesy of 1. Rayment.]...

If it is known that a particular form of relation, such as the power-law model, is applicable, it is not necessary to maintain a constant shear rate. Thus, for instance, a capillary tube viscometer can be used for determination of the values of the two parameters in the model. In this case it is usually possible to allow for the effects of wall-slip by making measurements with tubes covering a range of bores and extrapolating the results to a tube of infinite diameter. Details of the method are given by Farooqi and Richardson. 21 ... 

Richardson C, McKenzie D (1994) Radioactive diseqtrilibria from 2D models of melt generation by plumes and ridges. Earth Planet Sei Lett 128 425-437... 

Several models relating the isotopic effects of U-series disequilibria to the timescales of the melting process have now been proposed (e.g., McKenzie 1985 Williams and Gill 1989 Spiegelman and Elliott 1993 Qin 1992 Iwamori 1994 Richardson and McKenzie 1994). While these models differ mainly in their treatment of the melt extraction process (i.e., reactive porous flow vs near fractional melting), because they incorporate the effect... 

The ability of STM to image at the atomic scale is particularly exemplified by the two other chapters in the book. Thornton and Pang discuss the identification of point defects at Ti02 surfaces, a material that has played an important role in model catalyst studies to date. Point defects have been suggested to be responsible for much of the activity at oxide surfaces and the ability to identify these features and track their reactions with such species as oxygen and water represents a major advance in our ability to explore surface reactions. Meanwhile, Baddeley and Richardson concentrate on the effects of chirality at surfaces, and on the important field of surface chirality and its effects on adsorption, in a chapter that touches on one of the fundamental questions in the whole of science - the origins of life itself ... 

Sorbie, K. S., M. Yuan and M. M. Jordan, 1994, Application of a scale inhibitor squeeze model to improve field squeeze treatment design (SPE paper 28885). European Petroleum Conference Proceedings Volume (vol. 2 of 2), Society of Petroleum Engineers, Richardson, TX, pp. 179-191. 

Fig. 6. Schematic representation of the normal modes of an adsorbed diatomic molecule neglecting the surface structure, after Richardson and Bradshaw . In parentheses the experimentally measured values for CO in the ontop position on Pt(lll). (a) A frustrated translation (60 cm (b) A frustrated rotation (not yet detected), (c) The metal-molecule stretch (460cm ) . (d) The intramolecular stretch model (2100cm" ) . ...

Richardson and colleagues [3] identified a simple in vivo assay for the 5-HT3 receptor in man. They showed that the application of 5-HT to the exposed base of a blister evokes a pain and a wheal and flare response. These can be blocked by 5-HT3 receptor antagonists. Obviously one needs willing volunteers for such studies and suitable safety data must be available, but this is a useful model for assessing 5-HT3 receptor antagonist activity in man. 

Figure 6,9 Melting relations in Mg2Si04-Fe2Si04 system. Experimental data confirm validity of Richardson s (1956) ideal model for liquid. Reprinted from B. J. Wood and D. G. Fraser, Elementary Thermodynamics for Geologists, 1976, by permission of Oxford University Press.

The above is not intended to be a definitive list but rather to indicate some of the more commonly used models at the present time. Other, more historical, models have been used extensively, for example the polymerisation models of Toop and Samis (1962) and Masson (1965), the models of Flood (1954), Richardson (1956) and Yokakawa and Niwa (1969). More recently the central atom model by Satsri and Lahiri (1985, 1986) and the complex model of Hoch and Arpshofen (1984) have been proposed. Each has been used with some success in lower-order systems, but the extension to multicomponent systems is not always straightforward. 

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