Measurement of gold

For measuring low vapor pressures within the range from 1 to 10-6 torr, the well-known Knudsen effusion method was applied (see Section 2.2.). The alumina Knudsen cell was used for vapor pressure measurements of gold and of sodium chloride. The orifice is located in the center of the lid. 

The overall data may not be used in such an absolute sense as in analysis of a bronze casting, but they do provide some interesting information. Substantial concentrations of gold and arsenic were observed that appear to correlate with one another and with antimony concentration. Further work is needed to find authentic sources of the copper, tin, fluxes, and other materials used at these sites. Apparently, measurement of gold concentrations cannot be used to answer questions about a change in the sources of tin during this period. 

Gueroui, Z., Libchaber, A. (2004). Single-Molecule Measurements of Gold-Quenched Quantum Dots. PAyj. Rev. Lett. 93 166108. 

Near-Field Transmission Measurement of Gold Nanorods [68]... 

Andreu-Navarro, A., J. M. Fernandez-Romero, and A. Gomez-Hens. 2011. Determination of antioxidant additives in foodstuffs by direct measurement of gold nanoparticle formation using resonance light scattering detection. Anal. Chim. Acta 695 11-17. 

F. Wulff and C. D. Breach, Measurement of gold baUbond intermetaUic coverage. Gold Bulletin, 2006, 39(4), 175-184. 

In-situ stress measurements of gold films on glass substrates during thermal cychng, A. Katz, S. Nakahara and M. Geva, J. Appl. Phys., 1991, 70(12), 7343. 

Fig. 8.10 Size distribution for APC measurements of gold nanoparticles expressed as (a) radius (r) and (b) the number of atoms in an impacting nanoparticle." Reproduced by permission of The Royal Society of Chemistry...

The development of scanning probe microscopies and x-ray reflectivity (see Chapter VIII) has allowed molecular-level characterization of the structure of the electrode surface after electrochemical reactions [145]. In particular, the important role of adsorbates in determining the state of an electrode surface is illustrated by scanning tunneling microscopic (STM) images of gold (III) surfaces in the presence and absence of chloride ions [153]. Electrodeposition of one metal on another can also be measured via x-ray diffraction [154]. 

Figure 3.5 The apparent vapour pressure of gold in gas transportation measurements as a function of the gas flow rate. Low flow rates, which were used earlier to assure equilibrium, are now known to be too high as a result of thermal diffusion in the gas mixture which is saturated with gold vapour...

A series of force-distance curves for various materials pairs examined (gold/ nickel, diamond/graphite, diamond/diamond) are shown in Fig. 4 [39]. For an indentation, the unloading slope (dF/dr) of the force-displacement curve is a measure of the contact stiffness and can be used to determine the modulus if the contact area (A) is known using a variant of Eq. 3 below. 

In view of its susceptibility to sulphide tarnishing, silver may itself require some measure of protection in many decorative and industrial applications. Chromate passivation processes are commonly employed, but as an alternative, thin coatings of gold, rhodium or palladium may be used. 

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