نتایج جستجو برای: uranium deposit
تعداد نتایج: 26285 فیلتر نتایج به سال:
While the quantification of uranium is therefore demanding in the diluted sample, uranium isotope ratio determination requires the ultimate in instrumental performance as good precisions for large isotope ratios are required at low concentrations. The abundances of the three naturally occurring U isotopes are shown in Table 1, together with the 234U/238U and 235U/238U ratios. The nuclear indust...
BACKGROUND The deleterious impact of uranium on human health has been linked to its radioactive and heavy metal-chemical properties. Decades of research has defined the causal relationship between uranium mining/milling and onset of kidney and respiratory diseases 25 years later. OBJECTIVE We investigated the hypothesis that uranium, similar to other heavy metals such as cadmium, acts like es...
Uranium is ubiquitously found in drinking water and food. The gastrointestinal tract absorption fraction (f(1)) is an important parameter in risk assessment of uranium burdens from ingestion. Although absorption of uranium from ingestion has been studied extensively in the past, human data concerning children and adults are still limited. In a previous study based on measurements of uranium con...
The reported optical constants of uranium differ from that of vacuum significantly more than other elements do over the range of about 150 to 350 eV. This suggests that uranium could be used to produce high reflectance imaging mirrors for many soft x-ray applications. Elemental uranium is too chemically active to be used as a front surface mirror without protection. We computed the expected ref...
a solid chelating material, 1-(2-pyridy1azo)-2-naphthol (pan) supported on naphthalene provides a rapid and highly selective means of preconcentration of uranium from aqueous solution. uranium is quantitatively retained on this adsorbent in the ph range 9.8-10.7 with a flow rate of 1 ml min . the metal complex was desorbed with 10 ml of 2 m hydrochloric acid and uranium is determined by differe...
The Erzgebirge ('Ore Mountains') area in the eastern part of Germany was a major source of uranium for Soviet nuclear programs between 1945 and 1989. During this time, the former German Democratic Republic became the third largest uranium producer in the world. The high abundance of uranium in the geological formations of the Erzgebirge are mirrored in the discovery of uranium by M. Klaproth cl...
abstract uranium is a natural heavy metal widely dispersed across the earth crust. in many cases due to anthropogenic disturbance, it has been found beyond its natural abundance which resulted in soil-water pollution. the objective of this study was to investigate the capability of iranian natural zeolite clinoptilolite for removal of uranium (vi) from aqueous solutions. in order to optimize re...
The synthesis and spectroscopic characterization of the mononuclear uranium complex [((ArO)(3)tacn)U(III)(NCCH(3))] is reported. The uranium(III) complex reacts with organic azides to yield uranium(IV) azido as well as uranium(V) imido complexes, [((ArO)(3)tacn)U(IV)(N(3))] and [((ArO)(3)tacn)U(V)(NSi(CH(3))(3))]. Single-crystal X-ray diffraction, spectroscopic, and computational studies of thi...
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