نتایج جستجو برای: uranium compounds

تعداد نتایج: 235334  

2008
L. Havela K. Miliyanchuk J. Pešička A. P. Gonçalves J. C. Waerenborgh L.C.J. Pereira E. Šantavá

Magnetic properties of uranium-based compounds are related to the character of the 5f electronic states, ranging between a localized character and itinerancy (see e.g. [1]). UFe2 is the first uranium compound reported to exhibit ferromagnetism [2]. The Curie temperature TC given by various authors differs in some extent, but remains in the vicinity of 160 K in most of cases (see [1] and referen...

2001

T na m What Is Depleted Uranium? Depleted uranium is created as a byproduct during the processing of natural uranium to make it suitable for use as fuel in nuclear power plants or as a component in nuclear weapons. In natural uranium, 99.27% of the mass consists of atoms of uranium-238. About 0.72% of the mass consists of atoms of uranium-235, and a very small amount (0.0055% by mass) is uraniu...

2005
J. F. Kalinich

This paper discusses the development of and proposed enhancements to a colorimetric test for the detection of uranium in biological samples such as urine. The goal of this work is to develop a technique for the detection of uranium that could: 1) be conducted rapidly and accurately; 2) would not require extensive sample preparation; 3) would not require expensive or complicated instrumentation;...

Journal: :The journal of physical chemistry. A 2005
Hrant P Hratchian Jason L Sonnenberg P Jeffrey Hay Richard L Martin Bruce E Bursten H Bernhard Schlegel

Density functional theory is employed to investigate uranyl dihydroxide, UO2(OH)2, isomerization reaction energy barriers, including those occurring via proton shuttles. The ground-state structure of a uranyl dihydroxide complex containing a uranyl moiety with a near 90 degrees O=U=O bond angle is reported for the first time. Furthermore, we predict the vibrational spectra of these compounds. S...

Journal: :iranian journal of radiation research 0
h. garshasbi national radiation protection department, tehran, iran j. karimi diba m.h. jahanbakhshian s.k. asghari g.h. heravi

abstract   background : natural uranium exists in earth crust and seawater. the concentration of uranium might increase by human manipulation or geological changes. the aim of this study was to verify susceptibility of laser flourimetry method to determine the uranium concentration in caspian sea and persian gulf water.   materials and methods : laser flourimetric method was used to determine t...

1999

Biosorption of uranium metal ions by a nonliving protonated Sargassum fluitans seaweed biomass was used to remove the heavy metal uranium from the aqueous solution. Uranium biosorption isotherms were established for solution pH values ranging from pH 2.5-4.0. Uranium biosorption uptake was accompanied by the release of protons from the biomass. The sorption isotherms were highly pH dependent, a...

Journal: :آب و خاک 0
سعید باقریفام امیر لکزیان سیدجواد احمدی بهرام سلیمی آخرین فرید اصغری زاده

abstract uranium as a natural radioactive heavy metal widely disperses throughout the earth's crust. in many cases, the natural abundance has been re-distributed due to anthropogenic activities, resulting in radionuclide contamination in groundwater and surface soil. uranium through the plant uptake can enter the chain. the degree of speciation of radio nuclides in soils in areas with differing...

2006
Kondo Jun

The phenomenon of the resistance minimum in dilute magnetic alloys is explained in terms of the s-d interaction which takes account of scattering of the conduction electron off the magnetic impurities in metals. Some of the intermetallic compounds which involve rare earth elements or uranium show a very large electronic specific heat and remain non-magnetic even though they show a Curie-like su...

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 d...

H. Garshasbi, N. Alirezazadeh,

Background: Measurement of back ground concentration of uranium in drinking water is very important for many reasons, specially, for human health. The uranium concentration in drinking water in many counties is a matter of concern for clinical and radioactive poisoning. Materials and Methods: The uranium concentration in drinking water is determined using laser flourimatric uranium analyzer. Fo...

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