The self-absorption of γ-ray emitted from cylindrical fissile materials, such as 235 U and 239 Pu, does not possess spherical symmetry. The analytical formulae of self-absorption for γ-ray throughout the cylinder ha...The self-absorption of γ-ray emitted from cylindrical fissile materials, such as 235 U and 239 Pu, does not possess spherical symmetry. The analytical formulae of self-absorption for γ-ray throughout the cylinder have been obtained. The intensity of γ-ray is a function of γ-ray outgoing directions and cylindrical configurations, accordingly one can acquire the information about geometrical configuration of cylindrical fissile materials through multi-location measurements. Further more, the method is given in this article. The result can be applied to the fissile material safe- guard, such as nuclear monitoring and verifying.展开更多
This paper outlines briefly the role of nuclear medicine in life sciences and health care. Molecular imaging by using isotopic tracers can noninvasively visualize the chemistry or hidden process in the cells and tissu...This paper outlines briefly the role of nuclear medicine in life sciences and health care. Molecular imaging by using isotopic tracers can noninvasively visualize the chemistry or hidden process in the cells and tissues inside the body, obtaining "functional" images to provide early information of any disease and revealing the secrets of life. The vitality of nuclear medicine is its ability to translate bench into new clinical application that can benefits the patients. Although nuclear medicine community in China has made significant achievement with a great effort since 1950s, there are many obstacles to future development. Recommended measures are proposed here in an attempt to solve our existing problems.展开更多
文摘The self-absorption of γ-ray emitted from cylindrical fissile materials, such as 235 U and 239 Pu, does not possess spherical symmetry. The analytical formulae of self-absorption for γ-ray throughout the cylinder have been obtained. The intensity of γ-ray is a function of γ-ray outgoing directions and cylindrical configurations, accordingly one can acquire the information about geometrical configuration of cylindrical fissile materials through multi-location measurements. Further more, the method is given in this article. The result can be applied to the fissile material safe- guard, such as nuclear monitoring and verifying.
文摘This paper outlines briefly the role of nuclear medicine in life sciences and health care. Molecular imaging by using isotopic tracers can noninvasively visualize the chemistry or hidden process in the cells and tissues inside the body, obtaining "functional" images to provide early information of any disease and revealing the secrets of life. The vitality of nuclear medicine is its ability to translate bench into new clinical application that can benefits the patients. Although nuclear medicine community in China has made significant achievement with a great effort since 1950s, there are many obstacles to future development. Recommended measures are proposed here in an attempt to solve our existing problems.
