Incomplete idempotent Schröder quasigroups and related packing designs

Summary In this paper it is proved that, for any positive integern 2, 3 (mod 4),n 7, there exists an incomplete idempotent Schröder quasigroup with one hole of size two IISQ(n, 2) except forn = 10. It is also proved that for any positive integern 0, 1 (mod 4), there exists an idempotent Schröder quasigroup ISQ(n) except forn = 5 and 9. These results completely determine the spectrum of ISQ(n) and provide an application to the packing of a class of edge-coloured block designs.Research supported by NSERC grant A-5320.Research supported by NSFC grant 19231060-2.     

Fast neutron activation analysis: High resolution gamma spectroscopy

The purpose of this study was to demonstrate the versatility of combining the use of high resolution, Ge(Li) γ-detectors with the techniques of fast neutron activation analysis. A compilation of γ-ray spectra are presented for irradiation of 30 elements with 14.8 MeV neutrons under standard conditions and the origin of all major photopeaks is determined.