The Kapitza-Dirac effect is investigated in a formalism developed from the formal quantum theory. Nu merical calculations yield good agreement with the experimental results.
A quadratic scalar and vector coupling model proposed recently has been applied to finite nuclei.The calculated results are compared with those of the derivative scalar coupling (DSC) model and the nonlinear Walecka m...A quadratic scalar and vector coupling model proposed recently has been applied to finite nuclei.The calculated results are compared with those of the derivative scalar coupling (DSC) model and the nonlinear Walecka model The results show that the spin-orbit splittings are improved considerably by quadratic couplings in contrast to the DSC model However,the binding energy per nucleon,rms charge radius,as well as the spin-orbit splittings in the quadratic model are still small compared with those given by the nonlinear Walecka model and the experimental data.展开更多
Energy level statistics of a system consisting of six particles interacting by delta force in a two- model coupled with a deformed core is studied in particle-rotor model. For single- shell and two- shell the exact ...Energy level statistics of a system consisting of six particles interacting by delta force in a two- model coupled with a deformed core is studied in particle-rotor model. For single- shell and two- shell the exact energies for our statistical analysis are obtained from a full diagonalization of the Hamiltonian, while in two- case the configuration truncation is used. The nearest-neighbor distribution of energy levels and spectral rigidity are studied as the function of spin. The results of single- shell are compared with those in two- case. It is showed that the system becomes more regular when single- space is replaced by two- shell although the basis size of the configuration space is unchanged. The degree of chaoticity of the system, however, changes slightly when configuration space is enlarged by extending single- shell to two- shell .展开更多
In order to understand the molecules mechanism of ion irradiation,which has been widely used in many fields such as cancer therapy,uracil,one of the bases of nucleic acid.was chosen in the low energy ion radiolysis re...In order to understand the molecules mechanism of ion irradiation,which has been widely used in many fields such as cancer therapy,uracil,one of the bases of nucleic acid.was chosen in the low energy ion radiolysis research.The solid uracil films with mass thickness of 0.314mg/cm^2 were irradiated by 200keV H^+ ions .The experimental results show that 200keV H^+ ions are effective in decomposition of uracil molecules.One of the decomposition products,5,6-dihydro-uracil,was separated by high performance liquid chromatograph (HPLC) and detected using an UV-light detector.Its yield increases first but then decreases as the ion dose increasing.In addition,the mechanism of uracil decomposition and 5,6-dihydro-uracil formation was also disucssed.展开更多
GaN film grown on Si substrate was characterized by Rutherford backscattering/Channeling (RBS/C). The experimental results show that the thick- ness of GaN epilayer is about 2.5 μm and the GaN film has a good crystal...GaN film grown on Si substrate was characterized by Rutherford backscattering/Channeling (RBS/C). The experimental results show that the thick- ness of GaN epilayer is about 2.5 μm and the GaN film has a good crystalline quality (Xmin=3.3%). By using channeling angular scanning. the 0.35% of average tetragonal distortion in GaN layer is observed. In addition, the depth profiles of strain in GaN film layer reveal that the strain in GaN film nonlinearly decreases with the increase of film thickness. The strain-free thickness (above 2.5 μm) of GaN film on Si substrate is far below that (150μm) of GaN film on Sapphire.展开更多
The chaotic properties for six particles interacting by a monopole pairing force in a two-j shell model coupled with a deformed core are studied in the frame of particle-rotor model. The nearest-neighbor distribution ...The chaotic properties for six particles interacting by a monopole pairing force in a two-j shell model coupled with a deformed core are studied in the frame of particle-rotor model. The nearest-neighbor distribution of energy levels and spectral rigidity in the two-j shell are compared with those in the single-j case. The results show that the system is more regular in the two-j model than that in the single-j case.展开更多
Applying time-independent non-perturbative formalism to the photo-ionization of hydrogen atom immersed in a strong circularly polarized standing electromagnetic wave, we calculate the shift of energy levels and the di...Applying time-independent non-perturbative formalism to the photo-ionization of hydrogen atom immersed in a strong circularly polarized standing electromagnetic wave, we calculate the shift of energy levels and the distortion of wave functions for the hydrogen atom, the ionization cross section induced by the standing wave, and the angular distribution of photoelectrons and obtain some interesting results.展开更多
The 'waiting point' nuclide 93Pd has been produced via the 58Ni(40Ca, 3n2p) reaction. A helium-jet fast tape transport system was used in combination with p-7 coincidence measurement to identify the β-delayed...The 'waiting point' nuclide 93Pd has been produced via the 58Ni(40Ca, 3n2p) reaction. A helium-jet fast tape transport system was used in combination with p-7 coincidence measurement to identify the β-delayed proton precursor 93Pd, whose half-life has been measured to be (1.3±0.2) s. The measured展开更多
The very neutron-deficient nuclide ^129Pm was produced via the ^92Mo( ^40Ca, p2n) reaction and identified for the first time by using the X-γ coincidence in combination with a He-jet tape transport system. According ...The very neutron-deficient nuclide ^129Pm was produced via the ^92Mo( ^40Ca, p2n) reaction and identified for the first time by using the X-γ coincidence in combination with a He-jet tape transport system. According to the decay curve of a 99 keV γ-ray which corresponds to the known 5/2^- → 1/2^- transition in the daughter nucleus ^129Nd of ^129pm decay, the half-live of ^129pm was determined to be 2.4(9) s (see Fig.l). Based on the nuclear potential-energy surface (PES) calculations, the ground-state spin and parity of ^129pm was predicted as 5/2^- which is favorable to fecd a 5/2&- low-lying statc in the daughter nucleus ^129Nd via the (EC+/β+) decay.展开更多
Gallium Nitride (GaN) is an important material for the development of novel short-wave-length photonicdevices or high-frequency, high-power electronic devices. Ion implantation/irradiation was proved to be an effectiv...Gallium Nitride (GaN) is an important material for the development of novel short-wave-length photonicdevices or high-frequency, high-power electronic devices. Ion implantation/irradiation was proved to be an effective method to modify the physical properties of the material. In the present work, we studied the dependence of damage accumulation on irradiation dose and temperature and the corresponding effects on photolumines cence character of the material. Specimens of GaN (n-type doping, (0001) on axis) were irradiated with展开更多
The understanding of mechanisms of damage evolution in silicon carbide bombarded with energetic heliumions is important for the use of this material in future fusion reactors. One interesting result from our recentTEM...The understanding of mechanisms of damage evolution in silicon carbide bombarded with energetic heliumions is important for the use of this material in future fusion reactors. One interesting result from our recentTEM study of defect production in helium-implanted 4H-SiC is the rather high dose threshold for the forma-tion of nanometric helium bubbles This may supply an explanation for the observed defect depleted zone near the surface of silicon carbide. While the defect depleted zone is believed to be the reason of the high resistance of SiC nanocrystals and fibers to heavy irradiation.展开更多
基金国家自然科学基金，the Chinese High Performance Computing Center
文摘The Kapitza-Dirac effect is investigated in a formalism developed from the formal quantum theory. Nu merical calculations yield good agreement with the experimental results.
文摘A quadratic scalar and vector coupling model proposed recently has been applied to finite nuclei.The calculated results are compared with those of the derivative scalar coupling (DSC) model and the nonlinear Walecka model The results show that the spin-orbit splittings are improved considerably by quadratic couplings in contrast to the DSC model However,the binding energy per nucleon,rms charge radius,as well as the spin-orbit splittings in the quadratic model are still small compared with those given by the nonlinear Walecka model and the experimental data.
文摘Energy level statistics of a system consisting of six particles interacting by delta force in a two- model coupled with a deformed core is studied in particle-rotor model. For single- shell and two- shell the exact energies for our statistical analysis are obtained from a full diagonalization of the Hamiltonian, while in two- case the configuration truncation is used. The nearest-neighbor distribution of energy levels and spectral rigidity are studied as the function of spin. The results of single- shell are compared with those in two- case. It is showed that the system becomes more regular when single- space is replaced by two- shell although the basis size of the configuration space is unchanged. The degree of chaoticity of the system, however, changes slightly when configuration space is enlarged by extending single- shell to two- shell .
文摘In order to understand the molecules mechanism of ion irradiation,which has been widely used in many fields such as cancer therapy,uracil,one of the bases of nucleic acid.was chosen in the low energy ion radiolysis research.The solid uracil films with mass thickness of 0.314mg/cm^2 were irradiated by 200keV H^+ ions .The experimental results show that 200keV H^+ ions are effective in decomposition of uracil molecules.One of the decomposition products,5,6-dihydro-uracil,was separated by high performance liquid chromatograph (HPLC) and detected using an UV-light detector.Its yield increases first but then decreases as the ion dose increasing.In addition,the mechanism of uracil decomposition and 5,6-dihydro-uracil formation was also disucssed.
基金Supported by National Natural Science Foundation of China under grant(10075072)
文摘GaN film grown on Si substrate was characterized by Rutherford backscattering/Channeling (RBS/C). The experimental results show that the thick- ness of GaN epilayer is about 2.5 μm and the GaN film has a good crystalline quality (Xmin=3.3%). By using channeling angular scanning. the 0.35% of average tetragonal distortion in GaN layer is observed. In addition, the depth profiles of strain in GaN film layer reveal that the strain in GaN film nonlinearly decreases with the increase of film thickness. The strain-free thickness (above 2.5 μm) of GaN film on Si substrate is far below that (150μm) of GaN film on Sapphire.
文摘The chaotic properties for six particles interacting by a monopole pairing force in a two-j shell model coupled with a deformed core are studied in the frame of particle-rotor model. The nearest-neighbor distribution of energy levels and spectral rigidity in the two-j shell are compared with those in the single-j case. The results show that the system is more regular in the two-j model than that in the single-j case.
基金The project supported by National Natural Science Foundation of China under Grant No.10075004 with the calculations supported by the High Performance Computing Center of China (Beijing)
文摘Applying time-independent non-perturbative formalism to the photo-ionization of hydrogen atom immersed in a strong circularly polarized standing electromagnetic wave, we calculate the shift of energy levels and the distortion of wave functions for the hydrogen atom, the ionization cross section induced by the standing wave, and the angular distribution of photoelectrons and obtain some interesting results.
文摘The 'waiting point' nuclide 93Pd has been produced via the 58Ni(40Ca, 3n2p) reaction. A helium-jet fast tape transport system was used in combination with p-7 coincidence measurement to identify the β-delayed proton precursor 93Pd, whose half-life has been measured to be (1.3±0.2) s. The measured
文摘The very neutron-deficient nuclide ^129Pm was produced via the ^92Mo( ^40Ca, p2n) reaction and identified for the first time by using the X-γ coincidence in combination with a He-jet tape transport system. According to the decay curve of a 99 keV γ-ray which corresponds to the known 5/2^- → 1/2^- transition in the daughter nucleus ^129Nd of ^129pm decay, the half-live of ^129pm was determined to be 2.4(9) s (see Fig.l). Based on the nuclear potential-energy surface (PES) calculations, the ground-state spin and parity of ^129pm was predicted as 5/2^- which is favorable to fecd a 5/2&- low-lying statc in the daughter nucleus ^129Nd via the (EC+/β+) decay.
文摘Gallium Nitride (GaN) is an important material for the development of novel short-wave-length photonicdevices or high-frequency, high-power electronic devices. Ion implantation/irradiation was proved to be an effective method to modify the physical properties of the material. In the present work, we studied the dependence of damage accumulation on irradiation dose and temperature and the corresponding effects on photolumines cence character of the material. Specimens of GaN (n-type doping, (0001) on axis) were irradiated with
文摘The understanding of mechanisms of damage evolution in silicon carbide bombarded with energetic heliumions is important for the use of this material in future fusion reactors. One interesting result from our recentTEM study of defect production in helium-implanted 4H-SiC is the rather high dose threshold for the forma-tion of nanometric helium bubbles This may supply an explanation for the observed defect depleted zone near the surface of silicon carbide. While the defect depleted zone is believed to be the reason of the high resistance of SiC nanocrystals and fibers to heavy irradiation.
