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Contactless credit cards as a sub-division of smart cards offer a promising new market for RFID technologies. We consider in simulations, verified with experimental results, the way from the electrical supply power as required for the operation of contactless payment terminals to the card performance as required to allow a payment transaction within a limited time. For this purpose, we consider the paypass reference equipment, which is similar to a typical use case and specified to test product compliance.

IN order to prepare aluminium chloride for atomic weight determination, I burnt pure aluminium metal in a current of pure dry chlorine. Before starting the reaction, pure dry nitrogen was passed through the apparatus to expel the air. After this has been attained, the flow of nitrogen was stopped and a slow current of pure dry chlorine was allowed to pass over the metal. Since the pure dry gas reacts very slowly with aluminium at ordinary room temperature, the tube containing aluminium was heated to about 500° C. After the completion of the reaction, the aluminium chloride formed and a quantity of uncombined metal was cooled in a very slow stream of nitrogen. As the red heat ceased, a bright green phosphorescence appeared in the reaction tube surrounding small pieces of corroded uncombined metal.

As the International Committee on Atomic Weights has not provided a table since 1921, the British Sub-Committee published in the Journal of the Chemical Society of January last a revised table of atomic weights for 1929. In the report attached to this table we read that “for the nine ‘simple’ elements H, He, C, N, F, Na, P, As, and I the values obtained by F. W. Aston with his new mass-spectrograph are adopted in preference to those deduced from the physical or chemical data, because we are of opinion that, in these cases, Aston's method is less liable to error than any other”.…