Based on relativistic constituent quark (RCQ) model, the electric and magnetic form factors are analyzed. The ratio of the two form factors for the proton , which is an image of its charge and magnetization distributi...Based on relativistic constituent quark (RCQ) model, the electric and magnetic form factors are analyzed. The ratio of the two form factors for the proton , which is an image of its charge and magnetization distributions, is calculated in the light-front formulism of RCQ model. Recently, this ratio was measured at the Thomas Jefferson National Accelerator Facility (JLab) using the polarization technique. The new data presented span the range and are well described by a linear Q<SUP>2</SUP> fit. Also, the ratio reaches a constant value while Q<SUP>2</SUP> becomes larger than 2 (GeV)<SUP>2</SUP>. Our calculation results are presented and appear to be consistent with the experimental ones.展开更多
Many studies have observed that leaf wax δDn-alkane values differed significantly between woods and grasses in modern plants, with grasses D-depleted by 40 %0-70 ‰. The reasons for the differences in leaf wax δDn-a...Many studies have observed that leaf wax δDn-alkane values differed significantly between woods and grasses in modern plants, with grasses D-depleted by 40 %0-70 ‰. The reasons for the differences in leaf wax δDn-alkane values between woods and grasses, however, remain unclear. In this study, we measured the δD values of soil water （δDsw）, leaf water （δDlw）, and leaf wax n-alkane （δDn-alkane） for woods and grasses. We found no significant differences in the δD values of soil water （P = 0.82） and leaf water （P= 0.74） between the two life forms of plants. Therefore, the differences in leaf wax δDn-alkane values between woods and grasses may correlate with inherent properties of different plant life forms, such as leaf structures, biosynthetic processes, and leaf morphologies. Moreover, it is also possible that soil water with different 6Dsw at different depths utilized by woods and grasses may be responsible for some of the differences in leaf wax δDn-alkane values between the two life forms of plants, if woods mainly use soil water from the 〉100 cm depth, whereas grasses mainly use soil water from the 〈100 cm depth. The results of this work allow us to better understand the leaf wax δDn-alkane values of different plant life forms in a region.展开更多
A new model,called object model,for the simulation of cold roll-forming of tubes is presented.The model inherits the advantages of old models and is the embodiment of forming process that the strip is rolled step by s...A new model,called object model,for the simulation of cold roll-forming of tubes is presented.The model inherits the advantages of old models and is the embodiment of forming process that the strip is rolled step by step from feed rollers to last rolling pass.The elastic-plastic large deformation spline finite strip method based on updated Lagrangian method has been developed by improving the stiffness and transition matrix.Combined theory formulas and new analytical model,the forming process of a tube has been simulated successfully as an example.The analytical results are submitted and indicate that the proposed simulation method and new model are applicable.展开更多
In this paper, the Hausdorff dimension of the intersection of self-similar fractals in Euclidean space R^n generated from an initial cube pattern with an(n-m)-dimensional hyperplane V in a fixed direction is discussed...In this paper, the Hausdorff dimension of the intersection of self-similar fractals in Euclidean space R^n generated from an initial cube pattern with an(n-m)-dimensional hyperplane V in a fixed direction is discussed. The authors give a sufficient condition which ensures that the Hausdorff dimensions of the slices of the fractal sets generated by "multirules" take the value in Marstrand's theorem, i.e., the dimension of the self-similar sets minus one. For the self-similar fractals generated with initial cube pattern, this sufficient condition also ensures that the projection measure μVis absolutely continuous with respect to the Lebesgue measure L^m. When μV《 L^m, the connection of the local dimension ofμVand the box dimension of slices is given.展开更多
基金The project supported by the Science Foundation of Chinese Academy of Engineering Physics under Contract No.42103 and for Research Doctor Subsidizes (2001)
文摘Based on relativistic constituent quark (RCQ) model, the electric and magnetic form factors are analyzed. The ratio of the two form factors for the proton , which is an image of its charge and magnetization distributions, is calculated in the light-front formulism of RCQ model. Recently, this ratio was measured at the Thomas Jefferson National Accelerator Facility (JLab) using the polarization technique. The new data presented span the range and are well described by a linear Q<SUP>2</SUP> fit. Also, the ratio reaches a constant value while Q<SUP>2</SUP> becomes larger than 2 (GeV)<SUP>2</SUP>. Our calculation results are presented and appear to be consistent with the experimental ones.
文摘Many studies have observed that leaf wax δDn-alkane values differed significantly between woods and grasses in modern plants, with grasses D-depleted by 40 %0-70 ‰. The reasons for the differences in leaf wax δDn-alkane values between woods and grasses, however, remain unclear. In this study, we measured the δD values of soil water （δDsw）, leaf water （δDlw）, and leaf wax n-alkane （δDn-alkane） for woods and grasses. We found no significant differences in the δD values of soil water （P = 0.82） and leaf water （P= 0.74） between the two life forms of plants. Therefore, the differences in leaf wax δDn-alkane values between woods and grasses may correlate with inherent properties of different plant life forms, such as leaf structures, biosynthetic processes, and leaf morphologies. Moreover, it is also possible that soil water with different 6Dsw at different depths utilized by woods and grasses may be responsible for some of the differences in leaf wax δDn-alkane values between the two life forms of plants, if woods mainly use soil water from the 〉100 cm depth, whereas grasses mainly use soil water from the 〈100 cm depth. The results of this work allow us to better understand the leaf wax δDn-alkane values of different plant life forms in a region.
基金the National Natural Science Foundation of China (No. 50375135)the Talent Foundation of Beijing Jiaotong University (No. 2003RC059)
文摘A new model,called object model,for the simulation of cold roll-forming of tubes is presented.The model inherits the advantages of old models and is the embodiment of forming process that the strip is rolled step by step from feed rollers to last rolling pass.The elastic-plastic large deformation spline finite strip method based on updated Lagrangian method has been developed by improving the stiffness and transition matrix.Combined theory formulas and new analytical model,the forming process of a tube has been simulated successfully as an example.The analytical results are submitted and indicate that the proposed simulation method and new model are applicable.
基金supported by the National Natural Science Foundation of China(Nos.11371329,11471124,11071090,11071224,11101159,11401188)K.C.Wong Magna Fund in Ningbo University,the Natural Science Foundation of Zhejiang Province(Nos.LR13A010001,LY12F02011)the Natural Science Foundation of Guangdong Province(No.S2011040005741)
文摘In this paper, the Hausdorff dimension of the intersection of self-similar fractals in Euclidean space R^n generated from an initial cube pattern with an(n-m)-dimensional hyperplane V in a fixed direction is discussed. The authors give a sufficient condition which ensures that the Hausdorff dimensions of the slices of the fractal sets generated by "multirules" take the value in Marstrand's theorem, i.e., the dimension of the self-similar sets minus one. For the self-similar fractals generated with initial cube pattern, this sufficient condition also ensures that the projection measure μVis absolutely continuous with respect to the Lebesgue measure L^m. When μV《 L^m, the connection of the local dimension ofμVand the box dimension of slices is given.
