摘要：
冯·莱特(Georg Henryk Von Wright,1916-)是芬兰逻辑学家和哲学家,是现代道义逻辑的先驱.1951年冯·莱特的经典论文<道义逻辑>一文的发表,使道义逻辑的发展前进了重要的一步.在这篇文章中,冯·莱特提出了第一个富有生命力的道义逻辑系统.它的出现标志着现代道义逻辑历史的开端.
作者机构：
[张复兴] Department of Chemistry, Hengyang Teachers' College, 421008 Hengyang, China;Hunan Normal University, China;Chemistry Department, Hengyang Teachers' College, China;Chinese Chemical Society, China;[邝代治] Department of Chemistry, Hengyang Teachers' College, 421008 Hengyang, China, Hunan Normal University, China, Chemistry Department, Hengyang Teachers' College, China, Chinese Chemical Society, China
通讯机构：
[Kuang, D.] D;Department of Chemistry, Hengyang Teachers' College, China
作者机构：
Laser Spectroscopy Laboratory, Anhui Institute of Optics and Fine Mechanics, Academia Sinica, Hefei 230031, China;Department of Physics, Hengyang Teacher's College, Hengyang 421008, China
摘要：
A three-level Lambda-type atomic system is pumped by an incoherent radiation held. The system lases without population inversion in the steady state. We analyze the inversionless gain and origin of the gain.
作者机构：
[Xu, Wencheng; Liao, Changjun; Guo, Qi; Liu, Songhao; Wen, Shuangchun] South China Normal Univ, Guangzhou, China
摘要：
The propagation dynamics of dualfrequency CW signals in positive decreasingdispersion fibers(PDDF) was investigated by solving numerically the modified nonlinear Schrdinger equation. The CW signals can be compressed and finally evolute into fundamental dark soliton pulse. For a given initial pulse intensity or equivalent gain of the fiber, there exists an optimum distance where a dark soliton train is formed. The optimum distance vs the initial pulse amplitude and the equivalent gain of the PDDF are obtained numerically. The mechanism of the dark soliton generation is analysed and discussed.
