The survival probability of super heavy nuclei produced in cold fusion reactions is studied by using the standard Fermi gas level density formula and analyzed with fission and neutron evaporation characteristics predi...The survival probability of super heavy nuclei produced in cold fusion reactions is studied by using the standard Fermi gas level density formula and analyzed with fission and neutron evaporation characteristics predicted in different theoretical models. The level density formula used in this letter suppresses the ratio of neutron emission width to fission width, Гn/Гf. The dependence of Гn/Гf on the saddle point level density parameter and excitation energy is also investigated.展开更多
The properties of neutron stars are studied in a relativistic mean-field model with SU(2) chiral symmetry spontaneous breaking being considered. The calculation results indicate that the effects of the chiral symmetry...The properties of neutron stars are studied in a relativistic mean-field model with SU(2) chiral symmetry spontaneous breaking being considered. The calculation results indicate that the effects of the chiral symmetry spontaneous breaking are not negligible.展开更多
In DNS model, a key point is the calculation of PES because it governs the fusion dynamics and thus determines the optimum excitation energy of the compound nucleus and the optimum bombarding energy. Furthermore, it g...In DNS model, a key point is the calculation of PES because it governs the fusion dynamics and thus determines the optimum excitation energy of the compound nucleus and the optimum bombarding energy. Furthermore, it gives the information about the optimum projectile-target combination leading to a certain super-heavy nucleus.展开更多
To synthesize new superheavy nuclei a better understanding of the physics conception on the production mechanism is very important. Several theoretical models have been developed to describe the reaction dynamical mec...To synthesize new superheavy nuclei a better understanding of the physics conception on the production mechanism is very important. Several theoretical models have been developed to describe the reaction dynamical mechanism. Among them Adamian et al.have investigated the reaction mechanism of the superheavy element (SHE) formation in the concept of a dinuclear system (DNS) which is proved to be a powerful tool展开更多
So far super heavy elements are synthesized by cold fusion of heavy ions with Pb and Bi targets, or hot fusion reaction using 232Th, 238U and 242>244Pu targets. Further heavier synthesizing could be very difficult....So far super heavy elements are synthesized by cold fusion of heavy ions with Pb and Bi targets, or hot fusion reaction using 232Th, 238U and 242>244Pu targets. Further heavier synthesizing could be very difficult. The study of the fusion mechanism will hopefully propose optimal experimental conditions for the formation of the super heavy elements.展开更多
The survival probability of the excited compound nucleus is considered as one of the crucial factors for producing SHE. The competition between the neutron emission and the fission during the de-excitation process is ...The survival probability of the excited compound nucleus is considered as one of the crucial factors for producing SHE. The competition between the neutron emission and the fission during the de-excitation process is the main mechanism to determine the survival probability. The form of level density formula, the level展开更多
Different configurations for the monochroma-tor crystals and the analyzer crystals have been used in hard X-ray diffraction enhanced imaging (DEI) methods to over-come the complex task to adjust each of them to the id...Different configurations for the monochroma-tor crystals and the analyzer crystals have been used in hard X-ray diffraction enhanced imaging (DEI) methods to over-come the complex task to adjust each of them to the ideal position. Here we present a very compact DEI configuration, and preliminary results of experiments performed at the Beijing Synchrotron Radiation Facility (BSRF) using only two crystals: the first one acting as monochromator and the second one as analyzer in the Bragg geometry. Refraction contrast images characterized by high contrast and spatial resolution are obtained and compared with absorption im-ages. Differences among these images will be outlined and discussed emphasizing the potential capabilities of this very simple layout that guarantees a high transmission efficiency.展开更多
The ISM band at 2.4 GHz has mostly been used or planned for indoor systems.This band is also attractive for outdoor systems owing to the ease of the system deployment, as nofrequency licenses are required. In this pap...The ISM band at 2.4 GHz has mostly been used or planned for indoor systems.This band is also attractive for outdoor systems owing to the ease of the system deployment, as nofrequency licenses are required. In this paper, a multiple successive internal multireflection modelis used to estimate the complex electric permittivity at 2.4 GHz band. To obtain the data,measurements are performed at 160 MHz bandwidth centered about 2. 4 GHz using a vector networkanalyzer, which provides information about the amplitude and phase of transmission coefficient.Several samples of each material are measured and the results vary from sample to sample. It hasalso been found that some obstacles have polarization behaviour.展开更多
文摘The survival probability of super heavy nuclei produced in cold fusion reactions is studied by using the standard Fermi gas level density formula and analyzed with fission and neutron evaporation characteristics predicted in different theoretical models. The level density formula used in this letter suppresses the ratio of neutron emission width to fission width, Гn/Гf. The dependence of Гn/Гf on the saddle point level density parameter and excitation energy is also investigated.
文摘The properties of neutron stars are studied in a relativistic mean-field model with SU(2) chiral symmetry spontaneous breaking being considered. The calculation results indicate that the effects of the chiral symmetry spontaneous breaking are not negligible.
文摘In DNS model, a key point is the calculation of PES because it governs the fusion dynamics and thus determines the optimum excitation energy of the compound nucleus and the optimum bombarding energy. Furthermore, it gives the information about the optimum projectile-target combination leading to a certain super-heavy nucleus.
文摘To synthesize new superheavy nuclei a better understanding of the physics conception on the production mechanism is very important. Several theoretical models have been developed to describe the reaction dynamical mechanism. Among them Adamian et al.have investigated the reaction mechanism of the superheavy element (SHE) formation in the concept of a dinuclear system (DNS) which is proved to be a powerful tool
文摘So far super heavy elements are synthesized by cold fusion of heavy ions with Pb and Bi targets, or hot fusion reaction using 232Th, 238U and 242>244Pu targets. Further heavier synthesizing could be very difficult. The study of the fusion mechanism will hopefully propose optimal experimental conditions for the formation of the super heavy elements.
文摘The survival probability of the excited compound nucleus is considered as one of the crucial factors for producing SHE. The competition between the neutron emission and the fission during the de-excitation process is the main mechanism to determine the survival probability. The form of level density formula, the level
文摘Different configurations for the monochroma-tor crystals and the analyzer crystals have been used in hard X-ray diffraction enhanced imaging (DEI) methods to over-come the complex task to adjust each of them to the ideal position. Here we present a very compact DEI configuration, and preliminary results of experiments performed at the Beijing Synchrotron Radiation Facility (BSRF) using only two crystals: the first one acting as monochromator and the second one as analyzer in the Bragg geometry. Refraction contrast images characterized by high contrast and spatial resolution are obtained and compared with absorption im-ages. Differences among these images will be outlined and discussed emphasizing the potential capabilities of this very simple layout that guarantees a high transmission efficiency.
文摘The ISM band at 2.4 GHz has mostly been used or planned for indoor systems.This band is also attractive for outdoor systems owing to the ease of the system deployment, as nofrequency licenses are required. In this paper, a multiple successive internal multireflection modelis used to estimate the complex electric permittivity at 2.4 GHz band. To obtain the data,measurements are performed at 160 MHz bandwidth centered about 2. 4 GHz using a vector networkanalyzer, which provides information about the amplitude and phase of transmission coefficient.Several samples of each material are measured and the results vary from sample to sample. It hasalso been found that some obstacles have polarization behaviour.
