General principles reference signal

Although it is, in principle, feasible to quantify LEIS results, the determination of absolute ion fractions is far from trivial. In LEIS experiments, the surface composition is therefore generally obtained in a relative measurement by comparison of signals of the element in the sample of interest with those of reference samples, assuming that the matrix does not have a significant role and that the surface roughness is similar. 

Mr Bannister points out that no reference has been made to the safety of the general public, particularly on road works. Certainly the principles set out in 18-23 should be extended to cover this point. On the controlling of public traffic by signals, the use of automatic signals seems now to be almost universal even on the smallest jobs and offers the safest solution. Where manually... 

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