Chinese and Japanese leaders have long adhered to a tacit consensus on shelving the Diaoyu Islands dispute,effectively promoting their bilateral ties.The Abe cabinet should grasp the historical facts of Sino-Japanese ...Chinese and Japanese leaders have long adhered to a tacit consensus on shelving the Diaoyu Islands dispute,effectively promoting their bilateral ties.The Abe cabinet should grasp the historical facts of Sino-Japanese diplomacy,rapidly return to the tacit consensus and shelve the dispute to positively contribute to the development of Sino-Japanese relations.展开更多
Radiation uniformity is important for Z-pinch dynamic hohlraum driven fusion. In order to understand the radiation uniformity of Z-pinchdynamic hohlraum, the code MULTI-2D with a new developed magnetic field package i...Radiation uniformity is important for Z-pinch dynamic hohlraum driven fusion. In order to understand the radiation uniformity of Z-pinchdynamic hohlraum, the code MULTI-2D with a new developed magnetic field package is employed to investigate the related physical processeson Julong-I facility with drive current about 7e8 MA. Numerical simulations suggest that Z-pinch dynamic hohlraum with radiation temperaturemore than 100 eV can be created on Julong-I facility. Although some X-rays can escape out of the hohlraum from Z-pinch plasma and electrodes, the radiation field near the foam center is quite uniform after a transition time. For the load parameters used in this paper, the transitiontime for the thermal wave transports from r = 1 mm to r = 0 mm is about 2.0 ns. Implosion of a testing pellet driven by cylindrical dynamichohlraum shows that symmetrical implosion is hard to achieve due to the relatively slow propagation speed of thermal wave and the compressionof cylindrical shock in the foam. With the help of quasi-spherical implosion, the hohlraum radiation uniformity and corresponding pelletimplosion symmetry can be significantly improved thanks to the shape modulation of thermal wave front and shock wave front.展开更多
The step-like contrast structure for a class of nonlinear singularly perturbed optimal control problems is considered. The existence of the step-like contrast structure for the singularly perturbed optimal control pro...The step-like contrast structure for a class of nonlinear singularly perturbed optimal control problems is considered. The existence of the step-like contrast structure for the singularly perturbed optimal control problem is proved by equivalence, which is based on the necessary conditions. The authors not only give the conditions under which there exists a step-like contrast structure, but also determine where the internal transition time is. Meanwhile, the uniformly valid asymptotic expansion of the step-like contrast structure solution is constructed by the direct scheme method. Finally, an example is presented to show the result.展开更多
In a recent article in Nature,Mi and coworkers from the University of Michigan reported a solar-to-hydrogen(STH)efficiency of>9%in converting water into hydrogen and oxygen[1],which represents an important breakthr...In a recent article in Nature,Mi and coworkers from the University of Michigan reported a solar-to-hydrogen(STH)efficiency of>9%in converting water into hydrogen and oxygen[1],which represents an important breakthrough in this field due to the benchmarking leap in STH efficiency of photocatalytic overall water splitting under natural sunlight.展开更多
文摘Chinese and Japanese leaders have long adhered to a tacit consensus on shelving the Diaoyu Islands dispute,effectively promoting their bilateral ties.The Abe cabinet should grasp the historical facts of Sino-Japanese diplomacy,rapidly return to the tacit consensus and shelve the dispute to positively contribute to the development of Sino-Japanese relations.
基金This work was supported by the National Natural Science Foundation of China(Nos.11374357,11475153,11705282,and 11475260)Science Challenge Project(No.TZ2018001)+2 种基金Research Project of NUDT(Grant No.ZK16-03-29)the Spanish Ministerio de Economia y Competivida project(No.ENE2014-54960-R)the EUROfusion Consortium project AWP15-ENR-01/CEA-02.
文摘Radiation uniformity is important for Z-pinch dynamic hohlraum driven fusion. In order to understand the radiation uniformity of Z-pinchdynamic hohlraum, the code MULTI-2D with a new developed magnetic field package is employed to investigate the related physical processeson Julong-I facility with drive current about 7e8 MA. Numerical simulations suggest that Z-pinch dynamic hohlraum with radiation temperaturemore than 100 eV can be created on Julong-I facility. Although some X-rays can escape out of the hohlraum from Z-pinch plasma and electrodes, the radiation field near the foam center is quite uniform after a transition time. For the load parameters used in this paper, the transitiontime for the thermal wave transports from r = 1 mm to r = 0 mm is about 2.0 ns. Implosion of a testing pellet driven by cylindrical dynamichohlraum shows that symmetrical implosion is hard to achieve due to the relatively slow propagation speed of thermal wave and the compressionof cylindrical shock in the foam. With the help of quasi-spherical implosion, the hohlraum radiation uniformity and corresponding pelletimplosion symmetry can be significantly improved thanks to the shape modulation of thermal wave front and shock wave front.
基金supported by the National Natural Science Foundation of China (Nos. 11071075 and 11171113)the E-Institute of Shanghai Municipal Education Commission (No. E03004)the Knowledge Innovation Program of the Chinese Academy of Sciences (Nos. 30921064 and 90820307)
文摘The step-like contrast structure for a class of nonlinear singularly perturbed optimal control problems is considered. The existence of the step-like contrast structure for the singularly perturbed optimal control problem is proved by equivalence, which is based on the necessary conditions. The authors not only give the conditions under which there exists a step-like contrast structure, but also determine where the internal transition time is. Meanwhile, the uniformly valid asymptotic expansion of the step-like contrast structure solution is constructed by the direct scheme method. Finally, an example is presented to show the result.
文摘In a recent article in Nature,Mi and coworkers from the University of Michigan reported a solar-to-hydrogen(STH)efficiency of>9%in converting water into hydrogen and oxygen[1],which represents an important breakthrough in this field due to the benchmarking leap in STH efficiency of photocatalytic overall water splitting under natural sunlight.