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81.
共焦非稳腔中ps激光的内腔倍频 总被引:2,自引:1,他引:1
考虑倍频晶体相位匹配接收角(Angular acceptance)对倍频转换效率的影响,设计了正支(p支)共焦非稳腔Nd:YAP锁模激光器。平行光通过晶体实现完全相位匹配。以BBO和KTP作为腔内倍频元件,分别获得80.6%和60.2%的高效倍频转换,及几十mJ的绿光输出。同时实验测定其它有关参数。 相似文献
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基于带化学反应的二维轴对称Euler方程,利用带有Superbee限制函数的波传播算法,对共振腔中的氢气-空气预混气的聚心燃烧进行了数值模拟,讨论了共振腔不同抛物面对起爆的影响。数值结果表明,在开始阶段,燃烧诱导的激波在轴心、火焰和固壁的反射,使火焰失稳,随后共振腔中的抛物壁面上产生一定频率和强度的反射激波,不断穿越火焰,使火焰进一步失稳,加剧了燃烧速度,最终导致爆轰的形成。同时,火焰在与激波的作用过程中,形状扭曲变形,呈封闭端小敞口端大的扁平头部蘑菇云。共振腔抛物面的不同形状引起激波聚焦位置的变化,会影响激波和火焰的相互作用,使起爆提前或推迟,甚至不起爆。 相似文献
84.
We study the nonlinear phase response of a microring resonator coupled to a bus waveguide and the use of this nonlinear phase
shift to store information in the microring resonator and enhance the switching characteristics of a Mach-Zehnder interferometer
(MZI). By introducing coupling between adjacent microring resonators, the switching characteristics of the MZI can be exponentially
enhanced as a function of the number of microring resonators, when compared to the linear enhancement for uncoupled resonators.
With only a few moderate-finesse microring resonators, the switching power can be reduced to attowatt level, allowing for
photonic switching devices that operate at single-photon level in ordinary optical waveguides.
相似文献
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Based on the paraxial vectorial theory of beams propagating in uniaxially anisotropic media, we have derived the analytical propagation equations of beams generated by Gaussian mirror resonator (GMR) in uniaxial crystals, and given the typical numerical example to illustrate our analytical results. Due to the anisotropy crystals, the ordinary and extraordinary beams originated by incident beams generated by GMR propagate with different diffraction lengths, thus the linear polarization state and axial symmetry of the incident beams generated by GMR do not remain during propagating in crystals. 相似文献
88.
Simulated annealing and genetic algorithms for minimizing mean flow time in an open shop 总被引:1,自引:0,他引:1
Michael Andresen Heidemarie Brsel Marc Mrig Jan Tusch Frank Werner Per Willenius 《Mathematical and Computer Modelling》2008,48(7-8):1279-1293
This paper considers the problem of scheduling n jobs on m machines in an open shop environment so that the sum of completion times or mean flow time becomes minimal. It continues recent work by Bräsel et al. [H. Bräsel, A. Herms, M. Mörig, T. Tautenhahn, T. Tusch, F. Werner, Heuristic constructive algorithms for open shop scheduling to minmize mean flow time, European J. Oper. Res., in press (doi.10.1016/j.ejor.2007.02.057)] on constructive algorithms. For this strongly NP-hard problem, we present two iterative algorithms, namely a simulated annealing and a genetic algorithm. For the simulated annealing algorithm, several neighborhoods are suggested and tested together with the control parameters of the algorithm. For the genetic algorithm, new genetic operators are suggested based on the representation of a solution by the rank matrix describing the job and machine orders. Extensive computational results are presented for problems with up to 50 jobs and 50 machines, respectively. The algorithms are compared relative to each other, and the quality of the results is also estimated partially by a lower bound for the corresponding preemptive open shop problem. For most of the problems, the genetic algorithm is superior when fixing the same number of 30 000 generated solutions for each algorithm. However, in contrast to makespan minimization problems, where the focus is on problems with an equal number of jobs and machines, it turns out that problems with a larger number of jobs than machines are the hardest problems. 相似文献
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