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No abstract available

No abstract available

No abstract available

No abstract available

[en] Based on an analytical model of topological insulator, we present the quantum phase transitions of topological insulators with different symmetries by calculating their phase diagrams and edgestates. In particular, we show the symmetry protection nature of the topological quantum phase transitions. Topological quantum phase transitions cannot be classified by symmetries. However, the symmetry of the system plays an important role, where different topological quantum phase transitions are protected by different global symmetries

[en] Indirectly driven capsule implosions are driven by four shock waves whose strength and relative timing must be controlled to high precision to keep the fuel on a low adiabat. The symmetry during the first 2 ns should be tuned carefully. The mainline tuning targets chosen are the high Z re-emission spheres. For record of instantaneous asymmetry during the first 2 ns, multiple images in the time of the soft X-ray re-emission from a non-imploding Bi ball on SGⅡ facility were taken in 2011. The re-emitted images with hohlraum lengths of 1350 μm and 1500 μm were obtained and the experimental P_2/P_0 and P_4/P_0 time histories were deduced. A simple analytical view-factor model is established, and the simulation result of P_2/P_0 is in agreement with the measured P_2/P_0. (authors)

[en] CAP1400 reactor is quite different from traditional Gen. II nuclear power plants worldwide. The primary system of CAP1400 is modeled using RELAP5/MOD 3.3 code, and the transient thermal hydraulic characteristics are analyzed under the accident sequence of main steam line break (MSLB). DNBR of core is calculated by VIPRE code. Through summarizing the break spectrum, the results show that when the break size is less than 0.058 m' 2 , the reactor will not shut down;when the break size is between 0.059 m' 2 and 0.105 m' 2 , the reactor will shut down by overpower ΔT triggering reactor trip; and when the break size is between 0.106 m' 2 and 0.15 m' 2 , the reactor will shut down by the steam pipe low pressure injection signal. And the limited condition is 0.105 m' 2. The results of the limited condition show that the core heat flux and reactor coolant system temperature and pressure fluctuate with time. The minimum value of the DNBR is 1.914, greater than limited value 1.45. It indicates that CAP1400 reactor is very safe and reliable under the MSLB condition. (authors)

[en] The initiation events analysis and evaluation were the beginning of nuclear safety analysis and probabilistic safety analysis, and it was the key points of the nuclear safety analysis. Currently, the initiation events analysis method and experiences both focused on water reactor, but no methods and theories for thorium-based molten salt reactor (TMSR). With TMSR's research and development in China, the initiation events analysis and evaluation was increasingly important. The research could be developed from the PWR analysis theories and methods. Based on the TMSR's design, the theories and methods of its initiation events analysis could be researched and developed. The initiation events lists and analysis methods of the two or three generation PWR, high-temperature gascooled reactor and sodium-cooled fast reactor were summarized. Based on the TMSR's design, its initiation events would be discussed and developed by the logical analysis. The analysis of TMSR's initiation events was preliminary studied and described. The research was important to clarify the events analysis rules, and useful to TMSR's designs and nuclear safety analysis. (authors)

[en] Presented are the physical design, structure, fabrication and test result of the 476MHz subharmonic buncher, which is equipped on the high brightness injector of the Shanghai Free Electron Laser User Facility. The measurement results of the buncher are in good agreement with the design values