A nuclidic mass formula composed of a gross term, an even-odd term and a shell term is presented as a revised version of the mass formula constructed by the present authors and published in 2000. The gross term has almost the same functional form as in the previous formula, but the parameter values in it are somewhat different. The even-odd term is treated more carefully, and a considerable improvement is realized. The shell term is exactly the same as the previous one; it was obtained using spherical single-particle potentials and by treating the deformed nucleus as a superposition of spherical nuclei. The new mass formula is applicable to nuclei with Z ≥ 2 and N ≥ 2. The root-mean-square deviation from experimental masses is 666.7 keV, which is less than that of the previous mass formula, 689.8 keV. §1. IntroductionNuclear masses are important quantities to determine the ground state properties and reactions. Since the formulation of the Weizsäcker-Bethe nuclear mass formula, 1), 2) many mass predictions have been made. At the present time, the main purpose of the study of mass formulas is to predict reliable masses of unknown nuclides, especially neutron-rich nuclides and the superheavy nuclides. Some recent mass formulas have been applied to calculations of fission barriers and r-process nucleosyntheses.One way to reproduce the known nuclear mass values is to use mass systematics. For example, the mass formulas presented by Comay et al. and Jänecke et al. 3) are based on Garvey-Kelson-like systematics, 4) which take into consideration particle-hole configurations and yield accurate predictions of known experimental masses, though it is rather difficult to apply these formulas to unknown nuclei far from known ones. In the last decade, some mass predictions designed for wide nuclidic regions have been presented. Among these, we specifically mention two sophisticated mass formulas that give not only nuclear masses but also nuclear shapes

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The I-V characteristics of titanium contacts on polycrystalline diamond have been correlated with xray-photoelectron-spectroscopy (XPS) and Auger-electron-spectroscopy (AES) characterizations of the interface. As-deposited titanium contacts were rectifying in nature because of minimal interaction between as-deposited titanium and diamond as confirmed via XPS and AES. Once annealed, however, these contacts became Ohmic. The change was related to the formation of a carbide at the interface as observed by XPS. The Schottky-barrier height of the titanium contacts, which was determined by valence-band XPS, decreased from 1.3 to 0.8 eV as a result of the postdeposition annealing. It is believed that the carbide formation at the interface creates a diamond surface layer rich in electrically active defects which lower the barrier height of the metal and increase the leakage current. The interface between titanium and an argon-sputtered diamond surface was also characterized. Titanium formed asdeposited Ohmic contacts on the sputtered surface. A high density of ion-radiation-induced defects and a formation of a carbide during deposition both contributed to the Ohmic-contact formation. These contacts remained Ohmic after postdeposition annealing despite the fact that the annealing did not increase the carbide formed at the interface. It is believed that the carbide formed by the deposition of titanium behaved as a diffusion barrier to prevent the damaged layer from being annealed out into the titanium overlayer. It is concluded that most materials will yield rectifying contacts on a clean diamond surface. Ohmic contacts can be obtained by modifying the interface in some way (i.e. , carbide formation, sputtering, etc.).

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The β-decay half-lives of 38 neutron-rich isotopes from 36 Kr to 43 Mo and 116,117 Tc are reported here for the first time. These results when compared to previous standard models indicate an overestimation in the predicted half-lives by a factor of two or more in the A ≈ 110 region. A revised model based on the second generation gross theory of β decay better predicts the measured half-lives and suggests a more rapid flow of the rapid neutron-capture process (r-matter flow) through this region than previously predicted.About half of the elements heavier than Fe are thought to be produced in rapid neutron-capture process (rprocess) nucleosynthesis, a sequence of neutron-capture and β-decay processes. Although the astronomical site and the mechanism of the r-process are not yet fully understood, it is generally agreed that the process must occur in environments with extreme neutron densities. The study of the elemental distribution along the r-process path requires sensitive β-decay related information such as β-decay half-lives, β-delayed neutron-emission probabilities, and nuclear masses. In particular, determination of the timescale that governs matter flow from the r-process "seeds" to the heavy nuclei, as well as the distribution in the r-process peaks, depends sensitively on decay half-lives [1,2].Isotopes with extreme neutron-to-proton ratios in the mass region A = 110 − 125 have attracted special attention since theoretical r-process yields are found to underestimate isotopic abundances observed in the predicted global abundances by an order of magnitude or more [1,3,4]. This discrepancy has been investigated using numerous mass formulae that differ mainly in the strength of the nuclear shell closures [5,6]. The results indicate that considerable improvements in the global abundances of the isotopes can be achieved by assuming a quenching of the N = 82 shell gap. The properties of most of these crucial r-process nuclei are, however, currently unknown due to their extremely low production yields in the laboratory.A number of experimental studies on nuclei around neutron-rich krypton to technetium have been performed to investigate the region of the r-process path near N = 82 [7][8][9]. In the current work, we report on a first systematic study of the β-decay properties of very exotic, neutron-rich 36 Kr to 43 Tc nuclides that contribute to the r-process.Decay spectroscopy of very neutron-rich nuclei around A = 110 was performed at the recently-commissioned RIBF facility at RIKEN. A secondary beam, comprised of a cocktail of neutron-rich nuclei, was produced by inflight fission of a 345-MeV/nucleon 238 U beam in a 550-mg/cm 2 Be target. The primary beam was produced by the RIKEN cyclotron accelerator complex with a typical intensity ∼ 0.3 pnA at the production target posi-