[en] The rapid neutron-capture or the r-process is responsible for the origin of about half of the neutron-rich atomic nuclei in the universe heavier than iron. For the calculation of the abundances of those nuclei, atomic masses are required as one of the input parameters with very high precision. In the present work, the masses of the neutron rich Zn isotopes (A=71 to 81) lying in the r-process path have been measured in the ISOLTRAP experiment at ISOLDE/CERN. The mass of ⁸¹Zn has been measured directly for the rst time. The half-lives of the nuclides ranged from 46.5 h (⁷²Zn) down to 290 ms (⁸¹Zn). In case of all the nuclides, the relative mass uncertainty (Δm=m) achieved was in the order of 10^-8 corresponding to a 100-fold improvement in precision over previous measurements. (orig.)

No abstract available

[en] A parametrization of the MNDO method for the Zn atom is proposed. Calculations are performed for zinc-containing molecules and simple complexes. It is shown that the use of the parameters found in this study leads to more accurate estimates of enthalpies of formation of zinc compounds that can be obtained in MNDO calculations with Dewar's parameters. From a comparison of results of the calculations with experimental values and with data obtained in ab initio calculations, it is concluded that the MNDO method can be used in investigating various physicochemical properties of Zn compounds

[en] High-precision mass measurements on neutron-rich zinc isotopes ^71m,72-81Zn have been performed with the Penning trap mass spectrometer ISOLTRAP. For the first time, the mass of ⁸¹Zn has been experimentally determined. This makes ⁸⁰Zn the first of the few major waiting points along the path of the astrophysical rapid neutron-capture process where neutron-separation energy and neutron-capture Q-value are determined experimentally. The astrophysical conditions required for this waiting point and its associated abundance signatures to occur in r-process models can now be mapped precisely. The measurements also confirm the robustness of the N=50 shell closure for Z=30

[en] Isotope effects for zinc upon complex formation with dicyclohexano-18-crown-6 were investigated. The single stage separation factor for unit mass difference (α = 1.013) was great compared with that of calcium isotopes. One of the isotopes, ⁶⁷Zn, showed a larger isotope effect than the other isotopes of even mass number. 7 refs., 1 fig

[en] A new method, based on the simultaneous action of electron-beam zone melting with accelerated electrons with that of a pulse current, is suggested to enrich metals in stable isotopes. This technique makes it possible to obtain, in a relatively short time (several hours), a metal enriched up to 10% in individual isotopes; the metal being obtained in monocrystal form due to the use of the zone melting method. It is expected that the method may be suitable for manufactoring semiconductor materials of a modified ratio of stable isotopes. (author)

No abstract available

No abstract available

[en] The present investigation involves improved measurements of the Qsub(β)-values of ^75-78Zn and determinations of the total decay energies of sup(79,80)Zn which are not reported in the literature before. Also ⁸¹Zn was detected but at the time for the experiment the ion-source was not efficient enough to yield sufficient activity for an accurate Qsub(β)-determination. (orig./HSI)

[en] Highlights: • Rationally controlled multistage hydrothermal method to produce hierarchical ZnO nanorings with high surface-to-volume ratios and more exposed polar facets. • Hierarchical ZnO nanorings are produced by growing secondary nanowires on initial mono-morphological nanodisks. • Hierarchical ZnO nanorings show more enhanced performance as gas sensor. - Abstract: Morphology controlled hydrothermal synthesis techniques have been realised to produce hierarchical zinc oxide (ZnO) nanostructures with high surface-to-volume ratios and more exposed polar facets. Hierarchical ZnO nanorings (HNRs) were produced by growing secondary nanowires (NWs) on initial mono-morphological nanodisks (NDs). In the two steps of growth process, zinc sulphate and zinc nitrate were used as the source of zinc ions, respectively. In comparison with NWs and NDs, the grown HNRs showed more enhanced performance as gas sensors. HNRs were substantially sensitive and faster in responding to acetone. This high performance in gas sensing is due to the increased surface-to-volume ratio and small size of the NW building blocks as well as the increased proportion of (0 0 0 1) polar facets. This work represents a guide to structure induced improvement of sensing properties by controlling the morphology of nanostructures.