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[en] Excited structures in the neutron-deficient nucleus 179Hg have been established for the first time using the Gammasphere spectrometer in conjunction with the fragment mass analyzer. Competing states originating from three different minima associated with nearly spherical, oblate, and prolate deformations were found. This result can be contrasted with the situation in heavier odd-mass Hg isotopes where only two minima (oblate and prolate) have been seen. The implications of these three shapes at low spin and excitation energy are discussed in the general context of shape coexistence in this mass region.
[en] The purpose of this experiment is to investigate the retention of the radiomercury among the organs in mice. We used the healthy ICR male mice and divided into two groups. The experimental group was orally treated with squalene(200mg/kg of body weight< b.w>) at two times a day(12 hrs interval) and radiomercury(0.005 μCi/g of body weight.) only one time. The control group was treated only with radiomercury as same amount of the experimental group. As the result, main retentive organs were kidney, liver, blood, heart and skull. In the control group, all of these organs showed high retention of the radiomercury at 6 hours, but in the experimental groups, all the organs significantly inhibit retention of the radiomercury by squalene(p<0.05). We conclude that squalene inhibit retention of the radiomercury
[en] This work contains the results of the research of complete cycles of the centrifuge enrichment process of all mercury isotopes. As a result of this work, gram quantities of enriched isotopes of mercury by the centrifuge enrichment processes were obtained for the first time in the world.
[en] A method of photochemical separation of the mercury isotopes by the so-called indirect route in which a gas stream of oxygen and butadiene containing a mixture of mercury isotopes is passed through one or a number of vessels placed in series. The gas stream is irradiated by a lamp containing mercury which is depleted in one or a number of the isotopes and said isotopes are recovered in a trap placed downstream of the vessel or vessels
[en] The 1.00 m radius resolution mass spectromer at the University of Manitoba (Manitoba II) has been used to determine both atomic masses and atomic mass differences for all the naturally occurring isotopes of Hg with a precision superior to existing values. The mass difference data are in excellent agreement with recently tabulated values, while the atomic masses themselves differ significantly. (auth)
[en] This study investigated the mass dependent (MDF) and independent fractionation (MIF) of stable mercury isotopes in fish during the uptake and elimination of inorganic species. Mercury accumulation during the exposure led to re-equilibration of organ isotopic compositions with the external sources, and elimination terminated the equilibrating with isotope ratios moving back to the original values. Generally, the isotopic behaviors corresponded to the changes of Hg accumulation in the muscle and liver, causing by the internal transportation, organ redistribution, and mixing of different sources. A small degree of MDF caused by biotransformation of Hg in the liver was documented during the elimination, whereas MIF was not observed. The absence of MIF during geochemical and metabolic processes suggested that mercury isotopes can be used as source tracers. Additionally, fish liver is a more responsive organ than muscle to track Hg source when it is mainly composed of inorganic species. - Highlights: • Isotopic behavior of Hg(II) during the uptake and elimination by a marine fish was studied. • Hg isotopic fractionation in the organ corresponded to the changes of Hg bioaccumulation. • Internal transportation, redistribution and mixing of different sources explained the isotopic changes. • Mass dependent fractionation in the liver was found during Hg elimination. • Liver is more responsive than muscle to track Hg sources using Hg stable isotopes. - Fish liver is a more responsive organ than muscle when mercury stable isotopes are applied to track sources that are mainly composed of inorganic species.
[en] Within the framework of the dynamic collective model the excitation spectra and charge radii of the mercury isotopes are calculated. It is shown that the model describes well the entire existing set of experimental data and that the observed large changes in charge radii of the isotopes with A = 183 and 185 are related not to the transition from the oblate form to prolate with a large value of mean-square deformation, but merely to the increase of the effective charge on the nuclear surface
[en] A simple semi-empirical model based on the vibrational model is used to investigate the yrast bands of 178-188Pt and '182-198Hg isotopes. Additionally, the model overcomes the effect of the shape coexistence and shape transitions. This model gives a good fit to the observed small spacing between the 10+ and 12+ levels of 1'90Pt and the closely spaced triplet (8+, 10+ and 12+) structure in the energy spectra of 188-198Hg isotopes as compared with the other main models.
[en] Forest harvesting leads to changes in soil moisture, temperature and incident solar radiation, all strong environmental drivers of soil–air mercury (Hg) fluxes. Whether different forest harvesting practices significantly alter Hg fluxes from forest soils is unknown. We conducted a field-scale experiment in a northern Minnesota deciduous forest wherein gaseous Hg emissions from the forest floor were monitored after two forest harvesting prescriptions, a traditional clear-cut and a clearcut followed by biomass harvest, and compared to an un-harvested reference plot. Gaseous Hg emissions were measured in quadruplicate at four different times between March and November 2012 using Teflon dynamic flux chambers. We also applied enriched Hg isotope tracers and separately monitored their emission in triplicate at the same times as ambient measurements. Clearcut followed by biomass harvesting increased ambient Hg emissions the most. While significant intra-site spatial variability was observed, Hg emissions from the biomass harvested plot (180 ± 170 ng m"−"2 d"−"1) were significantly greater than both the traditional clearcut plot (− 40 ± 60 ng m"−"2 d"−"1) and the un-harvested reference plot (− 180 ± 115 ng m"−"2 d"−"1) during July. This difference was likely a result of enhanced Hg"2"+ photoreduction due to canopy removal and less shading from downed woody debris in the biomass harvested plot. Gaseous Hg emissions from more recently deposited Hg, as presumably representative of isotope tracer measurements, were not significantly influenced by harvesting. Most of the Hg tracer applied to the forest floor became sequestered within the ground vegetation and debris, leaf litter, and soil. We observed a dramatic lessening of tracer Hg emissions to near detection levels within 6 months. As post-clearcutting residues are increasingly used as a fuel or fiber resource, our observations suggest that gaseous Hg emissions from forest soils will increase, although it is not yet clear for how long such an effect will persist. - Highlights: • We investigated forestry impacts on gaseous Hg flux in a field experiment. • We measured ambient Hg fluxes and fluxes from added enriched Hg isotope tracers. • Biomass harvesting following clearcut had the greatest impact on ambient fluxes. • These impacts were seasonally restricted to the leaf-out growing season. • Isotope results suggest emissions dominated by legacy Hg pools