No abstract

diffuse. By the addition of sodium chloride, the deposit crystals became less and less lustrous and finally became dull and even blackish, similar to those obtained from a chloride bath (3). Such surfaces yielded clear diffraction patterns, revealing that the deposits had developed {211} + {1010},,~, orientations. That the loss of details of electron diffraction pattern in the above was not due to noncrystallinity, but due to adsorption of organic compounds, was shown from x-ray pattern of the stripped films, which consisted of rings indicating the crystalline nature of deposits. X-rays, because of their higher penetrating power, are scattered by the underlying metals, whereas electrons are scattered by surface layers which in the present case contained adsorbed additives. The alternate addition of naphthalene trisulfonate and sodium chloride made the deposits bright and dull, with their characteristic surface structures as discussed above.These results suggest that chloride ions facilitate the desorption process of the surface active compounds at the cathode surface and produce more sites for depositions, thus reducing the current density and hence contributing to lateral growth. The depolarization of cathode potential in a gelatine-copper sulfate bath with halide ions has been explained similarly (18). In the competition between chloride ions and surface active agents or other impurities to get adsorbed at the growing cathode surface, it is likely that the former, because of its polarizability (19), prevails over the others. This will also help the electron transfer process and favor lateral growth condition. The observation that chloride ions facilitate the deposition of metals (9-11) and the suggestion that the formation of chloro or aquo-complexes helps the electron transfer process during nickel deposition (12,13) are also in agreement with our results. ABSTRACTThe rate of jet electropolishing of low resistivity n-Si is controlled by two factors: supply of injected minority carriers and rate of dissolution of the SiO~ film. The current through the oxide changes from ionic to electronic, i.e., the silicon becomes passive, if the oxide thickness increases beyond a critical value. The hole supply determines the amount of etching which can occur when the Si is not passivated by a thick oxide layer.

A dynamic mechanical properties tester is described for use in the low audio and subaudio frequency range on various types of flabby material, including biological tissue. The moving element of the device is supported by a gas bearing with negligible springiness and friction and contains about 2.5 g of mass. A single coil in a magnetic field is used for both driving the moving element and measuring the vibration response.

No abstract