Discovery of Tantalum, Rhenium, Osmium, and Iridium Isotopes

Currently, thirty-eight tantalum, thirty-eight rhenium, thirty-nine osmium, and thirty-eight iridium, isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.Comment: To be published in At. Data Nucl. Data Table

Rethinking place-making: aligning placeness factors with perceived urban design qualities (PUDQs) to improve the built environment in historical district

Understanding the concept of place is critically important for urban design and place-making practice, and this research attempted to investigate the pathways by which perceived urban design qualities (PUDQs) influence placeness factors in the Chinese context. Twelve hypotheses were developed and combined in a structural equation model for validation. The Tanhualin historical district in Wuhan, China was selected for the analysis. As a result, place attachment was verified as a critical bridge factor that mediated the influence of PUDQs on place satisfaction. Among the five selected PUDQs, walkability and space quality were revealed as the most influential factors associated with place attachment and place satisfaction. Accessibility was actually indirectly beneficial to place-making via the mediation of walkability. Corresponding implications and strategies were discussed to maintain the sense of place for historic districts

Quelques résultats nouveaux sur la désintégration 221Pa - 227Ac

The 231Pa→ 227Ac disintegration 'is investigated by conversion electron spectrography and gamma spectrometry. Internal conversion coefficients, intensities and a new upper limit of the half-life are given for the most important transitions de-exciting the K = 1/2 — [530] rotational band.La désintégration 231Pa → 227Ac a été étudiée par spectrométrie γ et spectrographie des électrons de conversion. Les coefficients de conversion et les intensités des transitions les plus importantes qui désexcitent la bande de rotation K = 1/2 — [530] sont établies et une nouvelle limite de la période de ces transitions est donnée

Probabilités de transition E1 dans les isotopes de plomb de masse 200, 198, 196 et 194

The half-life of the first 5- levels has been measured for the following isotopes : 200Pb level energy : 1 908 keV T1/2 = 1.32 ± 0.07 ns 198Pb - 1 823.6 keV T1/2 = 49 ± 5 ns 196Pb — 1797.3 keV T1/2 = 130 ± 10 ns 194Pb - 1 819 keV T1/2 ≤ 5 ns The B(E1 ; 5- → 4+) transition probability is deduced. A microscopic calculation using a surface delta interaction with the Tamm-Dancoff approximation has been performed to evaluate the reduced transition probability ; the neutron states involved are h9/2, f7/2, i 13/2, p3/2, f5/2, p1/2, g9/2 and i11/2.La période du premier niveau 5- des noyaux suivants a été mesurée : 200Pb énergie du 5- : 1 908 keV T1/2 = 1,32 ± 0,07 ns 198Pb - 1 823,6 keV T1/2 = 49 ± 5 ns 196Pb — 1 797,3 keV T1/2 = 130 ± 10 ns 194Pb - 1 819 keV T1/2 ≤ 5 ns Un calcul microscopique des probabilités réduites de transition B(E1 ; 5- → 4+) a été réalisé en traitant une interaction delta de surface sur la base des états à deux quasi-particules ; les états de neutrons h 9/2, f7/2, i13/2, p3/2, f5/2, p1/2, g9/2, i11/2 sont pris en considération