 |
Atomic Energy Agency Lin Chengjian
The "Near Coulomb barrier heavy ion nuclear reaction mechanism" project completed by the Beijing National Tannery Accelerator National Laboratory, China National Institute of Atomic Energy, won the Beijing Science and Technology Award in 2014, mainly completed by Lin Chengjian, Jia Huiming, Liu Zuhua, Zhang Huanqiao and others.
Atomic nucleus is an important microscopic level of matter. It is a typical quantum multibody system. It contains abundant degrees of freedom and multiple basic interactions. Nuclear reactions are the means by which humans understand the microscopic world of the atomic nucleus and its movement patterns.
The study of low-energy nuclear reaction mechanisms not only deepens people's understanding of the nuclear world, but also is closely related to the national economy, and is expected to provide new mechanisms and approaches for humans to use nuclear energy. The Coulomb barrier is a key node in the low-energy region and is the transition point between the classical mechanism and the quantum mechanism. The project research team carried out innovative research based on the three major scientific issues of multi-channel coupling mechanism, exotic nuclear reaction mechanism, and superheavy nuclear synthesis mechanism in near-base nuclear reaction research.
The multi-channel coupling mechanism is a long-term focus in the study of near-barrier heavy ion nuclear reactions. There are many nuclei inside the heavy ions, and there are many reaction paths opened in the nuclear reaction, and many degrees of freedom are involved. In the low energy region, the reaction time is long and sufficient coupling can be achieved between the degrees of freedom. In near-barrier energy, coupling strongly changes the probability of barrier tunneling and forms multi-dimensional barrier tunneling.
The project carried out a deep-level mechanism study: In terms of the anomalies of the optical potential dispersion parameters, the project carried out a systematic study of more than ten systems. The target nucleus covers from heavy to medium heavy nuclei, from near spherical to deformed nuclei to spherical nuclei. Vast area. After considering the coupling tract effect, no abnormality of diffusion parameters was observed. The results show that this anomaly is an appearance of the unreviewed reaction mechanism on the optical potential, which eliminates people's doubt about the size of the nuclear surface dispersion.
In the study of the coupling tract effect of neutron transfer on the fusion reaction, the project carried out a series of comparative studies with and without positive Q-neutron transitions, pointing out the factors involved in the reaction such as nuclear structure and transfer mechanism. It provides abundant experimental materials for the development of coupled-channel theory and deepens people's understanding of multidimensional quantum tunneling phenomena.
The strange new nuclear reaction mechanism is a hot issue emerging in this century. The exotic core refers to the atomic nucleus with weak structure and strange structure. It will produce a special new mechanism in the nuclear reaction. In the study of the weakly-bound nuclear rupture effect, the project innovatively proposed the method of T+R+B=1 (where T, R, and B represent the penetration, reflection, and fracture probability, respectively), and investigated the weakly-bound nuclear reaction from the concept of probability flow. For the first time, the distribution of quasi-elastic barriers in weakly confined nuclear systems was measured, and it was pointed out that the distribution of potential barriers is a sensitive probe for investigating the effects of rupturing and continuous-state strong coupling.
This method opens up an effective way to study the effect of rupture and is used by many foreign laboratories. In the research of the optical potential of exotic nuclear systems, the project proposed a method of extracting the optical potential of the exotic nuclear system from the transfer reaction. Using stable nuclear beams to obtain high-precision experimental data, the optical potential of some unstable and exotic nuclear reactions was successfully extracted. This opens up new ideas for the study of the optical potential of exotic nuclear systems.
The mechanism of superheavy nucleosynthesis, related to the synthesis of superheavy elements, is a challenge that challenges the limit of the periodic table of elements. The elements heavier than uranium 92 are all artificially synthesized. The most important element in the synthesis is No. 118, but the probability of synthesis has reached the limit that human beings can detect. Therefore, many countries in the world have conducted research on mechanisms and expect to make breakthroughs in their synthetic approaches.
The project carried out research on the fusion-fission mechanisms of multiple medium- and heavy-duty systems, and deeply understood the dynamic evolution of mass, energy, and angular momentum in heavy ion reactions, providing experimental materials and mechanisms for the development of superheavy nuclear synthesis theory. The clues. In addition, the project carried out a prospective study of the theory of superheavy nuclear synthesis, discovered the exponential law of the residual nuclear cross section of fusion evaporation, predicted the best target combination and excitation function for the synthesis of element 117, and was used as a theoretical support for the synthesis of 117 elements. In the experiment, the fusion diffusion model was improved, and the coupling of neck and radial motion was considered for the first time, and the optimal conditions for the synthesis of element 118-120 were predicted. These theoretical work provide practical guidance for the synthesis of superheavy elements.
The project published 42 SCI academic papers, of which 23 were published in the American Physical Review C, the best academic journal in the field of nuclear physics. The results appraisal committee believes: “This is an invaluable research achievement in the field of low-energy nuclear physics in China in recent years. Overall, the project research has reached the international advanced level, and some of the researches are in a leading position.â€
High speed shutter door is a rapid operating, anti-crash shutter door for indoor application . The most advantage of this door is that the opening/closing speed can reach to 0.6-1.8m/s, really fast action a lot than tranditional rollling shutter door. short opening and closing times reduce cooling loss, avoid airflow and enable a smooth operating procedure. They can also be designed in larger dimensions for the mining and aircraft industries.
High Speed Door can be easily installed, economical,quiet and efficient with electromechanical drive.
This door quickly though in/out open gate, ideal for warehouses,factories, hangars use, widths can be from 2m to 20 meters.
The material of this door are variety: PVC curtain to keep the insdie clean, heavy duty aluminum door with wind-resisitant function can wrok in heavy windy weather, and also the freezer door can be used in cold warehouse or somewhere like that.
Including models are:PVC High Speed Door, Aluminum Spiral High Speed Door, Self-Recovery repair door, Cold Storage Room Fast Door.
High Speed Door
High Speed Door,PVC High Speed Door,Aluminum High Speed Door,Spiral High Speed Door
Shenzhen Hongfa Automatic Door Co., Ltd. , https://www.hongfadoor.com