In order to see if the 11-year solar activity could cause measurable variation in △<sup>14</sup>C concentration of atmosphere, we measured （cooperating with Chen Tie-mei, Yun Si-xun and Fan Chang-yun） t...In order to see if the 11-year solar activity could cause measurable variation in △<sup>14</sup>C concentration of atmosphere, we measured （cooperating with Chen Tie-mei, Yun Si-xun and Fan Chang-yun） the <sup>14</sup>C contents △<sup>C</sup> in AD1824—1925 tree rings of a white spruce, growing at the Mackenzie Delta（68°N,130°W） in Canada. The results are listed in Table 1.展开更多
According to the experiment results of X-ray diffraction and IR, the reduced partition function ratio (RPFR) and the contribution of various related vibration modes of uranium-crown ether complex (DCH18C6·H_3O)_2...According to the experiment results of X-ray diffraction and IR, the reduced partition function ratio (RPFR) and the contribution of various related vibration modes of uranium-crown ether complex (DCH18C6·H_3O)_2UO_2Cl_4 were theoreticallv calculated in detail. The equilibrium constant K_(eq) (that is, the single stage isotopic separation factor α) of exchange reaction for uranium isotopic chemical exchange system UO_2^(2+)(H_2O)_5—(DCH18C6.H_3O)_2UO_2Cl_4 is estimated to be 1.000746 at 12℃ and 1.000672 at 29℃, respectively, which are quite close to the experimental values 1.0010±0.0002 arid 1.0012±0.0004. Theoretical analysis shows that in the course of forming the complex of uranium with crown ether, the coordinated water of uranium is stripped, which performs a key action on the remarkable isotope effect for this system.展开更多
文摘In order to see if the 11-year solar activity could cause measurable variation in △<sup>14</sup>C concentration of atmosphere, we measured （cooperating with Chen Tie-mei, Yun Si-xun and Fan Chang-yun） the <sup>14</sup>C contents △<sup>C</sup> in AD1824—1925 tree rings of a white spruce, growing at the Mackenzie Delta（68°N,130°W） in Canada. The results are listed in Table 1.
基金Project supported by the National Natural Science Foundation of China.
文摘According to the experiment results of X-ray diffraction and IR, the reduced partition function ratio (RPFR) and the contribution of various related vibration modes of uranium-crown ether complex (DCH18C6·H_3O)_2UO_2Cl_4 were theoreticallv calculated in detail. The equilibrium constant K_(eq) (that is, the single stage isotopic separation factor α) of exchange reaction for uranium isotopic chemical exchange system UO_2^(2+)(H_2O)_5—(DCH18C6.H_3O)_2UO_2Cl_4 is estimated to be 1.000746 at 12℃ and 1.000672 at 29℃, respectively, which are quite close to the experimental values 1.0010±0.0002 arid 1.0012±0.0004. Theoretical analysis shows that in the course of forming the complex of uranium with crown ether, the coordinated water of uranium is stripped, which performs a key action on the remarkable isotope effect for this system.
