共查询到20条相似文献,搜索用时 62 毫秒
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利用粒子 -转子模型研究三轴超形变核态,讨论了区别轴对称超形变和三轴超形变可能的实验信息.为了直接从实验上识别三轴超形变带,必须同时测量能谱和电磁跃迁几率. Current developments in triaxial superdeformed states in nuclei are discussed from a theoretical perspective. A detailed analysis of superdeformed triaxial bands is made with particle-rotor model. Experimental information which may differentiate triaxial superdeformation from axially-symmetric superdeformation is disussed. In order to identify the superdeformed triaxial bands both the energy spectra and electromagnetic transition. 相似文献
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通过152Sm(19F,4n)167Lu反应观测到167Lu的一个新的转动带.发现其高自旋γ跃迁能量与163Lu和165Lu三轴超形变的十分相近.按基于推转壳模型的总转动位能面计算,167Lu和前人工作中的171Ta[660]1/2转动带被指定为三轴超形变带.讨论了该核区三轴超形变的形成机制. 相似文献
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In general relativity, the equation of motion of the spin is given by the equation of parallel transport, which is a result of the space-time geometry. Any result of the space-time geometry cannot be directly applied to gauge theory of gravity. In gauge theory of gravity, based on the viewpoint of the coupling between the spin and gravitational field,an equation of motion of the spin is deduced. In the post Newtonian approximation, it is proved that this equation gives the same result as that of the equation of parallel transport. So, in the post Newtonian approximation, gauge theory of gravity gives out the same prediction on the precession of orbiting gyroscope as that of general relativity. 相似文献
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简述了近20多年以来我们在稀土发光和光谱理论方面所做的主要工作、取得的进展和成果。包括:(1)关于(4f)N组态内单光子跃迁强度:推广Judd-Ofelt三参量公式,在其中计入"J混合"(偶宇称晶场成分造成的)导致的修正;澄清了国际上关于Judd-Ofelt全参量公式中"静力学项"和"动力学项"相对正负号的争论(仍为负号)。(2)关于(4f)N组态内双光子过程强度:提出直接计算强度方法(放弃缔合近似,利用Ce3+的5d和左邻RE3+的(4f)N能级-波函资料,近似模拟出最重要的虚中间组态(4f)N-15d的能级-波函结构)来讨论和改进Judd-Ofelt缔合近似。(3)固体中声子辅助的稀土离子间能量传输理论:发现HLO理论关于单声子过程中的"干涉相消"实际只适合于对角过程,而非对角过程则是"干涉相加",因而,后者首要的是单声子而非双声子过程;同时,用"晶体格波模"取代"Debye模"描述能量传输中的声子,给出了新模型下计算对角和非对角过程速率等物理量的整套公式。并由之看出:波矢q=0和对应色散曲线扁平段的光学声子对单声子非对角过程速率有完全不能忽略的贡献,这些都不同于或超出于HLO理论。(4)提出和发展了分析指认4f-5d跃迁光谱的简单理论模型,用能量和跃迁强度同时进行近似拟合,成功地分析指认了从(4f)3到(4f)13离子在几种基质中的4f→5d吸收(激发)谱,也成功用于若干5d→4f辐射谱。(5)对跃迁的初末晶场态同时引用有效自旋哈密顿描述稀土离子间超交换作用,成功地解释了低温10 K时立方结构的纯稀土冰晶石晶体Cs2NaLnCl6(Ln=Er,Yb)等的吸收谱中0声子线(量级为几个cm-1)的精细分裂。 相似文献
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The luminescence spectra of AgCl microcrystals were measured in two different regimes: in the regime of excitation of stationary luminescence and in the regime of photostimulated burst of luminescence. Differences between the spectra of stationary luminescence and the spectra of photostimulated-luminescence burst in the range between 430 and 590 nm have been found. The luminescence spectra are complex; the ratio of intensities for elementary components changes with the technique of excitation. Differences in the form and composition of complex luminescence bands obtained under different conditions of registration are attributed to the recombination interaction of the luminescence centers. It is shown that analysis of the dependences of intensity ratios for the elementary components of a complex luminescence band on the exciting-radiation intensity allows one to evaluate the mechanism of recombination in elementary bands provided that the mechanism is known for at least one luminescence band.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 1, pp. 85–89. January–February, 2005. 相似文献
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M.G. Edmunds 《Contemporary Physics》2013,54(4):263-285
Astronomers have two approaches to trying to determine the age of the Universe. They can estimate the ages of individual objects in the Universe and specifically in our Galaxy. These estimates use either the observed properties of stars and theoretical ideas concerning stellar evolution or the abundances of long-lived radioactive isotopes and their decay products. Alternatively they can use cosmological theories and observations to try to determine the age of the entire Universe. Obviously the Universe must be older than its component parts but neither of the above methods is sufficiently reliable that this is true of the deduced ages. As a result, it is from time to time reported that some object in the Universe is older than the Universe itself. In this article we discuss the methods that are currently being used to determine the age and we emphasize the problems in obtaining reliable results. It is not at present possible to provide a definite value for the age of the Universe. 相似文献
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H. Dandache 《Il Nuovo Cimento D》1989,11(10):1501-1506
Summary The semi-empirical Hugoniot equation of state is obtained by using the third-order tangency between the isentropic and the
Hugoniot curves at the origin of coordinates. The results of this model are in good agreement with Carter’s experimental data
for fourteen elements from the lanthanides series in the lower phase only.
Due to postal troubles with Lebanon, it was impossible to send proffs to the author as he requested. 相似文献
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In general relativity, the equation of motion of the spin is given by the equation of parallel transport, which is a result of the space-time geometry. Any result of the space-time geometry cannog be directly applied to gauge theory of gravity. In gauge theory of gravity, based on the viewpoint of the coupling between the spin and gravitational field, an equation of motlon of the spin is deduced. In the post Newtonian approximation, it is proved that this equation gives the same result as that of the equation of parallel transport. So, in the post Newtonian approximation, gauge theory of gravity gives out the same prediction on the precession of orbiting gyroscope as that of general relativity. 相似文献