نتایج جستجو برای: radioactive trace elements
تعداد نتایج: 351116 فیلتر نتایج به سال:
The long-lived radioactive element thorium can potentially provide a simple and direct clock to determine the age of our Galaxy. Spectroscopic investigations of thorium in metal-poor stars have yielded some promising initial results. We discuss the major observational and theoretical limitations in thorium cosmochronometry, and point out the ways in which the implied Galactic ages from thorium ...
The radioactive element astatine exists only in trace amounts in nature. Its properties can therefore only be explored by study of the minute quantities of artificially produced isotopes or by performing theoretical calculations. One of the most important properties influencing the chemical behaviour is the energy required to remove one electron from the valence shell, referred to as the ioniza...
In this research work a rather new method was used to detect trace elements of small quantities. For this, X-ray intensity enhancement effect and standard samples of BAS Company were employed. In the standard sample a small amount of Rubidium was present, which by adding some quantities of SrCo3 to the sample the XRF characteristic peaks of Rubidium were enhanced. This effect proved to be appli...
background: the present study was performed to investigate the effects of trace elements particularity se, zn and cu on tumor genesis in breast cancer. methods: the inhibitory effect of se, zn and cu, on telomerase activity was analyzed in human breast tumor tissues and breast cancer (t47d) cells. tissue specimens from 24 women with benign breast disease and 32 women with breast cancer specimen...
background and objectives: the present study was conducted to evaluate the presence of biochemical contents and trace elements, and detect phytochemicals in the edible part extracts of asparagus officinalis dc and chlorophytum comosum linn by hptlc. materials and methods: the biochemical contents and trace elements were determined by different biochemical methods, and trace elements’ presence w...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید