Symmetry plays an important pan in the research of the dynamical behavior of nonlinear sys- tem. It is proved in this paper that, for a class of centrosymmetric systems with parametric excitation, chaos behaves in cen...Symmetry plays an important pan in the research of the dynamical behavior of nonlinear sys- tem. It is proved in this paper that, for a class of centrosymmetric systems with parametric excitation, chaos behaves in centrosymmetric manner, which implies that chaos need not to be an unsymmetric dynamical state.展开更多
The crystal and molecular structures of [(C 3H 7O) 2PS 2] 2(CCDC No.217201) were determined by means of X-ray crystallography. It crystallized in a triclinic system with space group P1 and lattice parameters a=0....The crystal and molecular structures of [(C 3H 7O) 2PS 2] 2(CCDC No.217201) were determined by means of X-ray crystallography. It crystallized in a triclinic system with space group P1 and lattice parameters a=0.82794(3) nm, b=0.84764(2) nm, c=0.85034(3) nm, α=97.78(3)°, β=110.77(3)°, γ=94.95(3)°, V=0.54701(9) nm3, Z=1. In this molecule, the two diisopropyl dithiophosphate groups, [(C 3H 7O) 2PS 2] 2, which are parallel to each other, are linked by an S—S bond and there exist inversion centers in the molecule. In the structure, the PS bonds in the two dithiophosphate units are trans-oriented to each other.展开更多
Supermolecular crystal composed of p-nitrophenol, hexamethylenetetramine, phosphoric acid and water was obtained by supermolecular assembly. The crystal has a centrosymmetric structure with space group P21/c. The rela...Supermolecular crystal composed of p-nitrophenol, hexamethylenetetramine, phosphoric acid and water was obtained by supermolecular assembly. The crystal has a centrosymmetric structure with space group P21/c. The relative intensity and integral value of green frequency doubling of light from the crystal powder compared with that from KDP powder measured by pico-second Nd:YAG laser are 757.3 (KDP: 183.4) and 1771.7 (KDP: 423.98), respectively. In supermolecular crystal, due to the arrangement of centrosymmetric p-nitrophenol molecules in the inorganic-organic host framework formed by hexamethylenetetramine, phosphoric acid and water, the distances between the p-nitrophenol molecules with centrosymmetry are changed (N1A-O1A: 0.8158 nm, N1B’-O1B: 1.4450 nm, N1A-N1A’: 0.5837 nm, N1B’-N1B: 0.6898 nm), and the interaction between the dipoles becomes weak, which is easy for the ground state to turn into the excited state charge separated form, and generate the stable asymmetrical distribution of π-electron cloud density of quinonal structure, thus exhibiting SHG effect.展开更多
基金The project supported by National Natural Science Foundation of China
文摘Symmetry plays an important pan in the research of the dynamical behavior of nonlinear sys- tem. It is proved in this paper that, for a class of centrosymmetric systems with parametric excitation, chaos behaves in centrosymmetric manner, which implies that chaos need not to be an unsymmetric dynamical state.
基金Supported by the National Natural Science Foundation of China(No.2 0 2 75 0 2 0 ),the Natural Science Foundation ofShandong Province(No.Z2 0 0 2 B0 2 ) and the Outstanding Adult- Young Scientific Research Encouraging Foundation of Shan-dong Province
文摘The crystal and molecular structures of [(C 3H 7O) 2PS 2] 2(CCDC No.217201) were determined by means of X-ray crystallography. It crystallized in a triclinic system with space group P1 and lattice parameters a=0.82794(3) nm, b=0.84764(2) nm, c=0.85034(3) nm, α=97.78(3)°, β=110.77(3)°, γ=94.95(3)°, V=0.54701(9) nm3, Z=1. In this molecule, the two diisopropyl dithiophosphate groups, [(C 3H 7O) 2PS 2] 2, which are parallel to each other, are linked by an S—S bond and there exist inversion centers in the molecule. In the structure, the PS bonds in the two dithiophosphate units are trans-oriented to each other.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 69778022) the Natural Science Foundation of Liaoning Province (Grant No. 9810301001).
文摘Supermolecular crystal composed of p-nitrophenol, hexamethylenetetramine, phosphoric acid and water was obtained by supermolecular assembly. The crystal has a centrosymmetric structure with space group P21/c. The relative intensity and integral value of green frequency doubling of light from the crystal powder compared with that from KDP powder measured by pico-second Nd:YAG laser are 757.3 (KDP: 183.4) and 1771.7 (KDP: 423.98), respectively. In supermolecular crystal, due to the arrangement of centrosymmetric p-nitrophenol molecules in the inorganic-organic host framework formed by hexamethylenetetramine, phosphoric acid and water, the distances between the p-nitrophenol molecules with centrosymmetry are changed (N1A-O1A: 0.8158 nm, N1B’-O1B: 1.4450 nm, N1A-N1A’: 0.5837 nm, N1B’-N1B: 0.6898 nm), and the interaction between the dipoles becomes weak, which is easy for the ground state to turn into the excited state charge separated form, and generate the stable asymmetrical distribution of π-electron cloud density of quinonal structure, thus exhibiting SHG effect.
